Re: [WIRELESS-LAN] DHCP Lease Times
Thanks Lawson. Curious how you decided on two hours. Was that because session times are usually one hour? I like the idea of scopes with 50% utilization. Also very important to watch CPU/load and keep it low. In this scenario it does mean if your DHCP service fails - every user in your environment will be impacted within one hour right. How hard would it be to buy yourself more time in that regard? What would be the downside of say 24 hour leases? Thanks, Curtis From: The EDUCAUSE Wireless Issues Constituent Group Listserv <WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU> on behalf of Lawson Cassels <loca...@ilstu.edu> Sent: Tuesday, May 8, 2018 8:58 AM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] DHCP Lease Times We have a wireless system that sees roughly 30K unique clients pass through each day. Our address space is set up as a single large /17, as the Aruba controllers are extremely effective at controlling multicast and broadcast... no need to segment the IP space in my opinion. We have the default lease time set to 2 hours, with a maximum of 3 hours. Our address space typically sits at about 50% utilization. We feel that this is a good configuration, as it leaves extra space for special events, unknown emergencies, or address depletion attacks. The load on our Bluecat DHCP servers is well under 25% and they are extremely low end hardware, so it doesn't seem like 2 hours is too short. Lawson Cassels Network Engineer Infrastructure, Operations, and Networking Illinois State University p: 309-438-4318 On 5/8/2018 7:52 AM, Ian Lyons wrote: > If you have Airwave one of the may "dials" is how long is your average > connection. > > Mine is 28 minutes. > > I set my lease time for WiFi for 1 hour. I have a /19, which might be > overkill, but with AD based DNS, I have poor insight into the things that go > bump in the night (for DNS) > > If Cisco, I think there was a Prime option for this data too > > -Original Message- > From: The EDUCAUSE Wireless Issues Constituent Group Listserv > <WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU> On Behalf Of Curtis K. Larsen > Sent: Monday, May 7, 2018 7:17 PM > To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU > Subject: [WIRELESS-LAN] DHCP Lease Times > > Hello, > > I'm curious to see what process/algorithm others use when determining DHCP > lease times for your Wi-Fi networks. Assuming plenty of IP addresses, what > DHCP lease time is ideal to assign to clients in a WLAN with 90,000 unique > clients/day, where avg. user spends 3hrs connected , but some (maybe 20%) go > several days, Keep in mind that 90% are the same user/device every day. > > What level of DHCP pool utilization do you think is best? Have you found any > industry documentation on this? Thanks in advance. > > -Curtis > > ** > Participation and subscription information for this EDUCAUSE Constituent > Group discussion list can be found at http://www.educause.edu/discuss. > > ** > Participation and subscription information for this EDUCAUSE Constituent > Group discussion list can be found at http://www.educause.edu/discuss. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/discuss. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/discuss.
Re: DHCP Lease Times
I have run a report in Cisco Prime that shows the duration of the "last session". Based on this report I think our average is around three hours ...but it varies a lot. A /19 is pretty big. We have some /20's right now and I am thinking about possibly going bigger. It seems the rule most admins are following is to find the average session time and make your DHCP lease twice that time. My thinking is a little different than that. I think you should provide the maximum lease time you can while keeping your scopes less than 50% depleted. My goals are: (1) To reduce unnecessary DHCPDISCOVER messages because the client can simply renew (especially when 90% are the same clients everyday), and (2) Reduce the likelihood of impact to clients from a DHCP failure by maximizing the amount of time between DHCPRENEWs for clients. In other words, if the entire DHCP service fails and my renew time is 12 hours away - the DHCP admins have a little more time to resolve things. Thoughts? Thanks, Curtis From: The EDUCAUSE Wireless Issues Constituent Group Listserv <WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU> on behalf of Ian Lyons <ily...@rollins.edu> Sent: Tuesday, May 8, 2018 6:52 AM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] DHCP Lease Times If you have Airwave one of the may "dials" is how long is your average connection. Mine is 28 minutes. I set my lease time for WiFi for 1 hour. I have a /19, which might be overkill, but with AD based DNS, I have poor insight into the things that go bump in the night (for DNS) If Cisco, I think there was a Prime option for this data too -Original Message- From: The EDUCAUSE Wireless Issues Constituent Group Listserv <WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU> On Behalf Of Curtis K. Larsen Sent: Monday, May 7, 2018 7:17 PM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: [WIRELESS-LAN] DHCP Lease Times Hello, I'm curious to see what process/algorithm others use when determining DHCP lease times for your Wi-Fi networks. Assuming plenty of IP addresses, what DHCP lease time is ideal to assign to clients in a WLAN with 90,000 unique clients/day, where avg. user spends 3hrs connected , but some (maybe 20%) go several days, Keep in mind that 90% are the same user/device every day. What level of DHCP pool utilization do you think is best? Have you found any industry documentation on this? Thanks in advance. -Curtis ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/discuss. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/discuss. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/discuss.
Re: [WIRELESS-LAN] DHCP Lease Times
We have a wireless system that sees roughly 30K unique clients pass through each day. Our address space is set up as a single large /17, as the Aruba controllers are extremely effective at controlling multicast and broadcast... no need to segment the IP space in my opinion. We have the default lease time set to 2 hours, with a maximum of 3 hours. Our address space typically sits at about 50% utilization. We feel that this is a good configuration, as it leaves extra space for special events, unknown emergencies, or address depletion attacks. The load on our Bluecat DHCP servers is well under 25% and they are extremely low end hardware, so it doesn't seem like 2 hours is too short. Lawson Cassels Network Engineer Infrastructure, Operations, and Networking Illinois State University p: 309-438-4318 On 5/8/2018 7:52 AM, Ian Lyons wrote: If you have Airwave one of the may "dials" is how long is your average connection. Mine is 28 minutes. I set my lease time for WiFi for 1 hour. I have a /19, which might be overkill, but with AD based DNS, I have poor insight into the things that go bump in the night (for DNS) If Cisco, I think there was a Prime option for this data too -Original Message- From: The EDUCAUSE Wireless Issues Constituent Group Listserv <WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU> On Behalf Of Curtis K. Larsen Sent: Monday, May 7, 2018 7:17 PM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: [WIRELESS-LAN] DHCP Lease Times Hello, I'm curious to see what process/algorithm others use when determining DHCP lease times for your Wi-Fi networks. Assuming plenty of IP addresses, what DHCP lease time is ideal to assign to clients in a WLAN with 90,000 unique clients/day, where avg. user spends 3hrs connected , but some (maybe 20%) go several days, Keep in mind that 90% are the same user/device every day. What level of DHCP pool utilization do you think is best? Have you found any industry documentation on this? Thanks in advance. -Curtis ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/discuss. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/discuss. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/discuss.
RE: DHCP Lease Times
If you have Airwave one of the may "dials" is how long is your average connection. Mine is 28 minutes. I set my lease time for WiFi for 1 hour. I have a /19, which might be overkill, but with AD based DNS, I have poor insight into the things that go bump in the night (for DNS) If Cisco, I think there was a Prime option for this data too -Original Message- From: The EDUCAUSE Wireless Issues Constituent Group Listserv <WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU> On Behalf Of Curtis K. Larsen Sent: Monday, May 7, 2018 7:17 PM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: [WIRELESS-LAN] DHCP Lease Times Hello, I'm curious to see what process/algorithm others use when determining DHCP lease times for your Wi-Fi networks. Assuming plenty of IP addresses, what DHCP lease time is ideal to assign to clients in a WLAN with 90,000 unique clients/day, where avg. user spends 3hrs connected , but some (maybe 20%) go several days, Keep in mind that 90% are the same user/device every day. What level of DHCP pool utilization do you think is best? Have you found any industry documentation on this? Thanks in advance. -Curtis ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/discuss. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/discuss.
RE: DHCP Lease Times
Hi Curtis, I have 8k users daily, what I did is have an interface group with multiple /20 subnets "I have broadcast forwarding disabled so it shouldn't matter", and I use AAA override to send the interface group back when authentication is done. On the WLC side, it uses round robin for selecting the interface inside the interface group. Lease time I use is 8 hours which are the work time. Yahya Jaber. Sr. Wireless Engineer IT Network & Communications - Engineering Building 14, Level 3, Rm 308-WS07 KAUST 23955-6900 Thuwal, KSA Email yahya.ja...@kaust.edu.sa Office +966 (0) 12 8081237 Mobile +966 (0) 558697555 On Call Rotation Mobile: +966 54 470 1177 -Original Message- From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] On Behalf Of Curtis K. Larsen Sent: Tuesday, May 8, 2018 02:17 To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: [WIRELESS-LAN] DHCP Lease Times Hello, I'm curious to see what process/algorithm others use when determining DHCP lease times for your Wi-Fi networks. Assuming plenty of IP addresses, what DHCP lease time is ideal to assign to clients in a WLAN with 90,000 unique clients/day, where avg. user spends 3hrs connected , but some (maybe 20%) go several days, Keep in mind that 90% are the same user/device every day. What level of DHCP pool utilization do you think is best? Have you found any industry documentation on this? Thanks in advance. -Curtis ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/discuss. This message and its contents including attachments are intended solely for the original recipient. If you are not the intended recipient or have received this message in error, please notify me immediately and delete this message from your computer system. Any unauthorized use or distribution is prohibited. Please consider the environment before printing this email. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/discuss.
DHCP Lease Times
Hello, I'm curious to see what process/algorithm others use when determining DHCP lease times for your Wi-Fi networks. Assuming plenty of IP addresses, what DHCP lease time is ideal to assign to clients in a WLAN with 90,000 unique clients/day, where avg. user spends 3hrs connected , but some (maybe 20%) go several days, Keep in mind that 90% are the same user/device every day. What level of DHCP pool utilization do you think is best? Have you found any industry documentation on this? Thanks in advance. -Curtis ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/discuss.
RE: [WIRELESS-LAN] wireless LAN DHCP lease times?
Good idea. I will email our SE today. Thanks for the response. Marcelo Lew Wireless Enterprise Administrator University Technology Services University of Denver Desk: (303) 871-6523 Cell: (303) 669-4217 Fax: (303) 871-5900 Email: m...@du.edumailto:m...@du.edu From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] On Behalf Of Ryan Holland Sent: Wednesday, February 16, 2011 7:56 PM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] wireless LAN DHCP lease times? Marcelo, We are, too. We have /24s for our vlan pooling along with 15min lease times. Still seeing issues. I put that in quotes, because we are accurately running out leases. What we have found is that there is a threshold of number of vlans in a pool before the dispersion of clients across the pool becomes suboptimal. We have twenty-three /24s in a pool and it is not performing well. At this point, we're trying to conger up /23s for this pool instead, as fewer vlans will result in a better dispersion. That is a short-term fix however, and as things grow, we'll be back to square one looking for /22s. :-( The real fix is a better method of vlan pooling. We have submitted a feature request wherein users are placed into the first vlan until it is full, then the next, then the next. This, along with MobileIP, would result in a much better use of the available address space. If you, too, like this idea, please request the same via your system engineer. The more voices we have, the sooner it'll be implemented . . . maybe. -- Ryan Holland Network Engineer, Wireless Office of the Chief Information Officer The Ohio State University 614-292-9906 holland@osu.edumailto:holland@osu.edu On Feb 16, 2011, at 5:12 PM, Marcelo Lew wrote: What are you guys doing for DHCP lease times on your wireless networks? We have 30m with 15m renewals, but still running low on IPs. We have a large subnet pool of /24 subnets, but I think the walk and drive by users are the ones depleting the pools during the day. I am also seeing quite a discrepancy between IP Users and Associated Users in our Aruba Controllers. Associated users supposedly don't eat up an IP address, but this number closely matches our IP address availability for the wireless network. Thanks, Marcelo Marcelo Lew Wireless Enterprise Administrator University Technology Services University of Denver Desk: (303) 871-6523 Cell: (303) 669-4217 Fax: (303) 871-5900 Email: m...@du.edumailto:m...@du.edu Spamhttps://antispam.osu.edu/b.php?i=1156745045m=975f46b54866c=s Not spamhttps://antispam.osu.edu/b.php?i=1156745045m=975f46b54866c=n Forget previous votehttps://antispam.osu.edu/b.php?i=1156745045m=975f46b54866c=f . ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. . ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
wireless LAN DHCP lease times?
What are you guys doing for DHCP lease times on your wireless networks? We have 30m with 15m renewals, but still running low on IPs. We have a large subnet pool of /24 subnets, but I think the walk and drive by users are the ones depleting the pools during the day. I am also seeing quite a discrepancy between IP Users and Associated Users in our Aruba Controllers. Associated users supposedly don't eat up an IP address, but this number closely matches our IP address availability for the wireless network. Thanks, Marcelo Marcelo Lew Wireless Enterprise Administrator University Technology Services University of Denver Desk: (303) 871-6523 Cell: (303) 669-4217 Fax: (303) 871-5900 Email: m...@du.edumailto:m...@du.edu . ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
Re: [WIRELESS-LAN] DHCP lease times?
On 9/14/10 11:32 AM, James F Eyrich wrote: Has any one looked at running significantly longer lease times? We are looking at the possibility of NATing our wireless service, moving to large private IP subnets for the clients and not needing to recycle addresses so often. We have discussed moving from the current 1 hour lease to 8 or 12 hours. thoughts? Our lease times are 4-10 days. Does chew up addresses, but most of those devices stay here anyway, so we're not really wasting addresses on passersby. -- Best regards -- Cal Frye, Network Administrator, Oberlin College Mudd Library, x.56930 -- CIT will NEVER ask you for your password! www.calfrye.com, www.oberlin.edu/cit/ What are your car's brakes for? They permit you to drive faster... Control is the key. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
Re: [WIRELESS-LAN] DHCP lease times?
Ohio State moved from one hour lease times to 15 minutes lease times. (Be sure to match your ARP timeout in your core with whatever DHCP lease time you choose.) == Ryan Holland Network Engineer, Wireless Office of the Chief Information Officer The Ohio State University 614-292-9906 holland@osu.edu On Sep 13, 2010, at 5:47 PM, Marcelo Lew wrote: What do you guys use for DHCP lease times on your wireless networks (external DHCP server)? We have an issue were our DHCP server (Cisco) reports subnets almost full, however, the Aruba Controller shows plenty IPs available. I think the issue might be related with devices getting on the network for a very short time, going off line, but the DHCP server still holds that lease. We have lease times set at 1hour for the wireless network. Shorter lease times maybe? Thanks, Marcelo Marcelo Lew Wireless Enterprise Administrator University Technology Services University of Denver Desk: (303) 871-6523 Cell: (303) 669-4217 Fax: (303) 871-5900 Email: m...@du.edu Spam Not spam Forget previous vote ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
Re: [WIRELESS-LAN] DHCP lease times?
At UMass Amherst we have 30 minute lease times. Mike Michael Dickson 413.545.9639 Network Analyst Univ. of Massachusetts Amherst On 9/14/2010 9:08 AM, Ryan Holland wrote: Ohio State moved from one hour lease times to 15 minutes lease times. (Be sure to match your ARP timeout in your core with whatever DHCP lease time you choose.) == Ryan Holland Network Engineer, Wireless Office of the Chief Information Officer The Ohio State University 614-292-9906 holland@osu.edu mailto:holland@osu.edu On Sep 13, 2010, at 5:47 PM, Marcelo Lew wrote: What do you guys use for DHCP lease times on your wireless networks (external DHCP server)? We have an issue were our DHCP server (Cisco) reports subnets almost full, however, the Aruba Controller shows plenty IPs available. I think the issue might be related with devices getting on the network for a very short time, going off line, but the DHCP server still holds that lease. We have lease times set at 1hour for the wireless network. Shorter lease times maybe? Thanks, Marcelo */Marcelo Lew/* */Wireless Enterprise Administrator/* */University Technology Services/* */University of Denver/* */Desk: (303) 871-6523/* */Cell: (303) 669-4217/* */Fax: (303) 871-5900/* */Email: m...@du.edu mailto:m...@du.edu/* Spam https://antispam.osu.edu/b.php?i=1085496440m=512976112a11c=s Not spam https://antispam.osu.edu/b.php?i=1085496440m=512976112a11c=n Forget previous vote https://antispam.osu.edu/b.php?i=1085496440m=512976112a11c=f ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
RE: DHCP lease times?
University of South Florida is at 15 minutes for unencrypted networks, one hour for WPA2 authenticated networks. Toivo Voll Network Administrator Information Technology Communications University of South Florida From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:wireless-...@listserv.educause.edu] On Behalf Of Marcelo Lew Sent: Monday, September 13, 2010 17:47 To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: [WIRELESS-LAN] DHCP lease times? What do you guys use for DHCP lease times on your wireless networks (external DHCP server)? We have an issue were our DHCP server (Cisco) reports subnets almost full, however, the Aruba Controller shows plenty IPs available. I think the issue might be related with devices getting on the network for a very short time, going off line, but the DHCP server still holds that lease. We have lease times set at 1hour for the wireless network. Shorter lease times maybe? Thanks, Marcelo Marcelo Lew Wireless Enterprise Administrator University Technology Services University of Denver Desk: (303) 871-6523 Cell: (303) 669-4217 Fax: (303) 871-5900 Email: m...@du.edu ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
RE: [WIRELESS-LAN] DHCP lease times?
At Stonehill College we use a 30min lease time which works well for us. Mark From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:wireless-...@listserv.educause.edu] On Behalf Of Marcelo Lew Sent: Monday, September 13, 2010 5:47 PM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: [WIRELESS-LAN] DHCP lease times? What do you guys use for DHCP lease times on your wireless networks (external DHCP server)? We have an issue were our DHCP server (Cisco) reports subnets almost full, however, the Aruba Controller shows plenty IPs available. I think the issue might be related with devices getting on the network for a very short time, going off line, but the DHCP server still holds that lease. We have lease times set at 1hour for the wireless network. Shorter lease times maybe? Thanks, Marcelo Marcelo Lew Wireless Enterprise Administrator University Technology Services University of Denver Desk: (303) 871-6523 Cell: (303) 669-4217 Fax: (303) 871-5900 Email: m...@du.edu ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
Re: [WIRELESS-LAN] DHCP lease times?
30 minutes at Washburn as well. We had the same issue as what you described. No issues with the shorter lease time since we changed it 3 years ago. Heath On 9/13/2010 4:47 PM, Marcelo Lew wrote: What do you guys use for DHCP lease times on your wireless networks (external DHCP server)? We have an issue were our DHCP server (Cisco) reports subnets almost full, however, the Aruba Controller shows plenty IPs available. I think the issue might be related with devices getting on the network for a very short time, going off line, but the DHCP server still holds that lease. We have lease times set at 1hour for the wireless network. Shorter lease times maybe? Thanks, Marcelo */Marcelo Lew/* */Wireless Enterprise Administrator/* */University Technology Services/* */University of Denver/* */Desk: (303) 871-6523/* */Cell: (303) 669-4217/* */Fax: (303) 871-5900/* */Email: m...@du.edu/* ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. -- Heath Barnhart, CCNA Network Administrator Information Systems and Services Washburn University Topeka, KS 66621 ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
RE: [WIRELESS-LAN] DHCP lease times?
We run on half an hour lease times at Heriot-Watt University, Edinburgh as well. I had the lease time set to 15 minutes for a while, but this didn't seem to release IP addresses in any great numbers at peak times when we most needed the leases available and just put more load on our DHCP servers. Many Thanks Peter Mr Peter Methven, Network Specialist Information Technology (IT) Allen McTernan Building, Edinburgh Campus Tel: 0131 451 3516 For IT support queries or requests, please email ith...@hw.ac.uk mailto:ith...@hw.ac.uk or phone ext 4045, with full details of your query or request and your contact details. http://www.hw.ac.uk/it From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:wireless-...@listserv.educause.edu] On Behalf Of heath.barnhart Sent: 14 September 2010 16:01 To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] DHCP lease times? 30 minutes at Washburn as well. We had the same issue as what you described. No issues with the shorter lease time since we changed it 3 years ago. Heath On 9/13/2010 4:47 PM, Marcelo Lew wrote: What do you guys use for DHCP lease times on your wireless networks (external DHCP server)? We have an issue were our DHCP server (Cisco) reports subnets almost full, however, the Aruba Controller shows plenty IPs available. I think the issue might be related with devices getting on the network for a very short time, going off line, but the DHCP server still holds that lease. We have lease times set at 1hour for the wireless network. Shorter lease times maybe? Thanks, Marcelo Marcelo Lew Wireless Enterprise Administrator University Technology Services University of Denver Desk: (303) 871-6523 Cell: (303) 669-4217 Fax: (303) 871-5900 Email: m...@du.edu ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. -- Heath Barnhart, CCNA Network Administrator Information Systems and Services Washburn University Topeka, KS 66621 ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. -- Heriot-Watt University is a Scottish charity registered under charity number SC000278. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
Re: [WIRELESS-LAN] DHCP lease times?
Has any one looked at running significantly longer lease times? We are looking at the possibility of NATing our wireless service, moving to large private IP subnets for the clients and not needing to recycle addresses so often. We have discussed moving from the current 1 hour lease to 8 or 12 hours. thoughts? -- James Eyrich Team Lead Network Design Wireless Service Manager CITES - Networking - Network Design and Support - Network Design Group University of Illinois eyr...@illinois.edu 217-265-6867 On 9/14/2010 10:13 AM, Methven, Peter J wrote: We run on half an hour lease times at Heriot-Watt University, Edinburgh as well. I had the lease time set to 15 minutes for a while, but this didn’t seem to release IP addresses in any great numbers at peak times when we most needed the leases available and just put more load on our DHCP servers. Many Thanks Peter Mr Peter Methven, Network Specialist Information Technology (IT) Allen McTernan Building, Edinburgh Campus Tel: 0131 451 3516 For IT support queries or requests, please email ith...@hw.ac.ukmailto:ith...@hw.ac.uk or phone ext 4045, with full details of your query or request and your contact details. http://www.hw.ac.uk/it From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:wireless-...@listserv.educause.edu] On Behalf Of heath.barnhart Sent: 14 September 2010 16:01 To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] DHCP lease times? 30 minutes at Washburn as well. We had the same issue as what you described. No issues with the shorter lease time since we changed it 3 years ago. Heath On 9/13/2010 4:47 PM, Marcelo Lew wrote: What do you guys use for DHCP lease times on your wireless networks (external DHCP server)? We have an issue were our DHCP server (Cisco) reports subnets almost full, however, the Aruba Controller shows plenty IPs available. I think the issue might be related with devices getting on the network for a very short time, going off line, but the DHCP server still holds that lease. We have lease times set at 1hour for the wireless network. Shorter lease times maybe? Thanks, Marcelo Marcelo Lew Wireless Enterprise Administrator University Technology Services University of Denver Desk: (303) 871-6523 Cell: (303) 669-4217 Fax: (303) 871-5900 Email: m...@du.edumailto:m...@du.edu ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. -- Heath Barnhart, CCNA Network Administrator Information Systems and Services Washburn University Topeka, KS 66621 ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. Heriot-Watt University is a Scottish charity registered under charity number SC000278. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
RE: [WIRELESS-LAN] DHCP lease times?
Thank you all for the information! Marcelo Lew Wireless Enterprise Administrator University Technology Services University of Denver Desk: (303) 871-6523 Cell: (303) 669-4217 Fax: (303) 871-5900 Email: m...@du.edu From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:wireless-...@listserv.educause.edu] On Behalf Of Methven, Peter J Sent: Tuesday, September 14, 2010 9:14 AM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] DHCP lease times? We run on half an hour lease times at Heriot-Watt University, Edinburgh as well. I had the lease time set to 15 minutes for a while, but this didn't seem to release IP addresses in any great numbers at peak times when we most needed the leases available and just put more load on our DHCP servers. Many Thanks Peter Mr Peter Methven, Network Specialist Information Technology (IT) Allen McTernan Building, Edinburgh Campus Tel: 0131 451 3516 For IT support queries or requests, please email ith...@hw.ac.ukmailto:ith...@hw.ac.uk or phone ext 4045, with full details of your query or request and your contact details. http://www.hw.ac.uk/it From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:wireless-...@listserv.educause.edu] On Behalf Of heath.barnhart Sent: 14 September 2010 16:01 To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] DHCP lease times? 30 minutes at Washburn as well. We had the same issue as what you described. No issues with the shorter lease time since we changed it 3 years ago. Heath On 9/13/2010 4:47 PM, Marcelo Lew wrote: What do you guys use for DHCP lease times on your wireless networks (external DHCP server)? We have an issue were our DHCP server (Cisco) reports subnets almost full, however, the Aruba Controller shows plenty IPs available. I think the issue might be related with devices getting on the network for a very short time, going off line, but the DHCP server still holds that lease. We have lease times set at 1hour for the wireless network. Shorter lease times maybe? Thanks, Marcelo Marcelo Lew Wireless Enterprise Administrator University Technology Services University of Denver Desk: (303) 871-6523 Cell: (303) 669-4217 Fax: (303) 871-5900 Email: m...@du.edumailto:m...@du.edu ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. -- Heath Barnhart, CCNA Network Administrator Information Systems and Services Washburn University Topeka, KS 66621 ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. Heriot-Watt University is a Scottish charity registered under charity number SC000278. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
Re: [WIRELESS-LAN] DHCP lease times?
If you have unlimited address space such as with NAT you might be ok. Wireless users tend to be a transient bunch. We found that every time a local-loop bus goes by an outdoor AP about a dozen devices associate and grab an IP address from our open (cp) SSID. We also see a lot of devices turn on and get an IP but never authenticate. In these cases the user has not intention of using the network - maybe they're just writing a paper in Word - but their device sets up anyway. Because of these ghost users having an 8+ hour lease time could eat up a lease pool pretty quick. This issue is most prevalent with an open SSID. Using 802.1x will virtually eliminate the issue of drive-by lease grabbers. Mike Michael Dickson 413.545.9639 Network Analyst Univ. of Massachusetts Amherst On 9/14/2010 11:32 AM, James F Eyrich wrote: Has any one looked at running significantly longer lease times? We are looking at the possibility of NATing our wireless service, moving to large private IP subnets for the clients and not needing to recycle addresses so often. We have discussed moving from the current 1 hour lease to 8 or 12 hours. thoughts? ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
Re: [WIRELESS-LAN] DHCP lease times?
Depends on how big the subnet is. I'd still keep it small just to keep the leases open. Probably around 4 hours. That should give you a good balance of lease time versus load on the dhcp server. If the subnet was for a specific location were the user pool was going to be static in size and constant, such as a residential hall, long lease times could be beneficial. Heath On 9/14/2010 10:32 AM, James F Eyrich wrote: Has any one looked at running significantly longer lease times? We are looking at the possibility of NATing our wireless service, moving to large private IP subnets for the clients and not needing to recycle addresses so often. We have discussed moving from the current 1 hour lease to 8 or 12 hours. thoughts? -- Heath Barnhart, CCNA Network Administrator Information Systems and Services Washburn University Topeka, KS 66621 ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
Re: [WIRELESS-LAN] DHCP lease times?
We're running a whopping 3 *days *now. I like it because addresses stay consistent among the student body. If I see an IP addresses involved in something I can often know who it came from. A year ago it was just 5 minute leases, because we had a 255.255.254.0 subnet for wifi. Bumped that to 255.255.248.0, increased the lease time, and we've had zero problems. But we're a small school (500 students) in a small town, and so lease space really isn't an issue. Joel Coehoorn IT Director, York College 402.363.5603 On Tue, Sep 14, 2010 at 10:32 AM, James F Eyrich eyr...@illinois.eduwrote: Has any one looked at running significantly longer lease times? We are looking at the possibility of NATing our wireless service, moving to large private IP subnets for the clients and not needing to recycle addresses so often. We have discussed moving from the current 1 hour lease to 8 or 12 hours. thoughts? -- James Eyrich Team Lead Network Design Wireless Service Manager CITES - Networking - Network Design and Support - Network Design Group University of Illinois eyr...@illinois.edu 217-265-6867 On 9/14/2010 10:13 AM, Methven, Peter J wrote: We run on half an hour lease times at Heriot-Watt University, Edinburgh as well. I had the lease time set to 15 minutes for a while, but this didn’t seem to release IP addresses in any great numbers at peak times when we most needed the leases available and just put more load on our DHCP servers. Many Thanks Peter Mr Peter Methven, Network Specialist Information Technology (IT) Allen McTernan Building, Edinburgh Campus Tel: 0131 451 3516 For IT support queries or requests, please email ith...@hw.ac.ukmailto: ith...@hw.ac.uk or phone ext 4045, with full details of your query or request and your contact details. http://www.hw.ac.uk/it From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto: wireless-...@listserv.educause.edu] On Behalf Of heath.barnhart Sent: 14 September 2010 16:01 To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] DHCP lease times? 30 minutes at Washburn as well. We had the same issue as what you described. No issues with the shorter lease time since we changed it 3 years ago. Heath On 9/13/2010 4:47 PM, Marcelo Lew wrote: What do you guys use for DHCP lease times on your wireless networks (external DHCP server)? We have an issue were our DHCP server (Cisco) reports subnets almost full, however, the Aruba Controller shows plenty IPs available. I think the issue might be related with devices getting on the network for a very short time, going off line, but the DHCP server still holds that lease. We have lease times set at 1hour for the wireless network. Shorter lease times maybe? Thanks, Marcelo Marcelo Lew Wireless Enterprise Administrator University Technology Services University of Denver Desk: (303) 871-6523 Cell: (303) 669-4217 Fax: (303) 871-5900 Email: m...@du.edumailto:m...@du.edu ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. -- Heath Barnhart, CCNA Network Administrator Information Systems and Services Washburn University Topeka, KS 66621 ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. Heriot-Watt University is a Scottish charity registered under charity number SC000278. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
DHCP lease times?
What do you guys use for DHCP lease times on your wireless networks (external DHCP server)? We have an issue were our DHCP server (Cisco) reports subnets almost full, however, the Aruba Controller shows plenty IPs available. I think the issue might be related with devices getting on the network for a very short time, going off line, but the DHCP server still holds that lease. We have lease times set at 1hour for the wireless network. Shorter lease times maybe? Thanks, Marcelo Marcelo Lew Wireless Enterprise Administrator University Technology Services University of Denver Desk: (303) 871-6523 Cell: (303) 669-4217 Fax: (303) 871-5900 Email: m...@du.edu ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
RE: DHCP lease times?
At Emory, we've been using 1 hour lease times for our wireless subnets for 5 years. This has worked well for us over the years. As wireless gained popularity (and massive amounts of users/devices), we moved to private IP addresses to handle the load. We are still using the 1 hour lease time for wireless even though we now have plenty of IP addresses. We did have an issue when school started where one area sucked up over 1000 IP addresses with users having 2 or more devices - we added subnets to handle the additional load using Aruba's VLAN pooling. - Stan Brooks - CWNA/CWSP Emory University University Technology Services 404.727.0226 AIM/Y!/Twitter: WLANstan MSN: wlans...@hotmail.commailto:wlans...@hotmail.com GoogleTalk: wlans...@gmail.commailto:wlans...@gmail.com From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:wireless-...@listserv.educause.edu] On Behalf Of Marcelo Lew Sent: Monday, September 13, 2010 5:47 PM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: [WIRELESS-LAN] DHCP lease times? What do you guys use for DHCP lease times on your wireless networks (external DHCP server)? We have an issue were our DHCP server (Cisco) reports subnets almost full, however, the Aruba Controller shows plenty IPs available. I think the issue might be related with devices getting on the network for a very short time, going off line, but the DHCP server still holds that lease. We have lease times set at 1hour for the wireless network. Shorter lease times maybe? Thanks, Marcelo Marcelo Lew Wireless Enterprise Administrator University Technology Services University of Denver Desk: (303) 871-6523 Cell: (303) 669-4217 Fax: (303) 871-5900 Email: m...@du.edu ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. This e-mail message (including any attachments) is for the sole use of the intended recipient(s) and may contain confidential and privileged information. If the reader of this message is not the intended recipient, you are hereby notified that any dissemination, distribution or copying of this message (including any attachments) is strictly prohibited. If you have received this message in error, please contact the sender by reply e-mail message and destroy all copies of the original message (including attachments). ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
Re: [WIRELESS-LAN] DHCP lease times?
We started with 3 hour lease times, had pool issues, then tweaked a few times and ended up at 20min lease times. We've been running like that for over a year now. You may have to experiment a bit to find what lease time works best for your network Our controllers (Aruba) are set to flush dead hosts/macs/users after 18 minutes of no activity from the client Ken Connell Intermediate Network Engineer Computer Communication Services Ryerson University 350 Victoria St RM AB50 Toronto, Ont M5B 2K3 416-979-5000 x6709 -Original Message- From: Marcelo Lew m...@du.edu Sender: The EDUCAUSE Wireless Issues Constituent Group Listserv WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Date: Mon, 13 Sep 2010 15:47:16 To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Reply-to: The EDUCAUSE Wireless Issues Constituent Group Listserv WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: [WIRELESS-LAN] DHCP lease times? What do you guys use for DHCP lease times on your wireless networks (external DHCP server)? We have an issue were our DHCP server (Cisco) reports subnets almost full, however, the Aruba Controller shows plenty IPs available. I think the issue might be related with devices getting on the network for a very short time, going off line, but the DHCP server still holds that lease. We have lease times set at 1hour for the wireless network. Shorter lease times maybe? Thanks, Marcelo Marcelo Lew Wireless Enterprise Administrator University Technology Services University of Denver Desk: (303) 871-6523 Cell: (303) 669-4217 Fax: (303) 871-5900 Email: m...@du.edu ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
Re: [WIRELESS-LAN] DHCP lease times?
Indiana University is using 20 minute lease times very successfully. -Jason On Sep 13, 2010, at 5:47 PM, Marcelo Lew wrote: What do you guys use for DHCP lease times on your wireless networks (external DHCP server)? We have an issue were our DHCP server (Cisco) reports subnets almost full, however, the Aruba Controller shows plenty IPs available. I think the issue might be related with devices getting on the network for a very short time, going off line, but the DHCP server still holds that lease. We have lease times set at 1hour for the wireless network. Shorter lease times maybe? Thanks, Marcelo Marcelo Lew Wireless Enterprise Administrator University Technology Services University of Denver Desk: (303) 871-6523 Cell: (303) 669-4217 Fax: (303) 871-5900 Email: m...@du.edu ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found athttp://www.educause.edu/groups/. ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
