It is expected from an 802.11 perspective.  May not be desirable, but that is 
how the wireless standard works.  Unicasting RAs over the air fixes this.

Sent from my iPhone

> On Mar 18, 2015, at 12:42 PM, Frans Panken <[email protected]> wrote:
> 
> No, it is not. The result is that it breaks IPv6 on local VLANs: clients 
> receive multiple prefixes on local VLANs. 
> 
> Jake Snyder schreef op 18/03/15 om 17:51:
>> Leaking of RAs between VLANS is expected behavior as RA are multicast.  
>> Because the 802.11 protocol sends multicast traffic as broadcast over the 
>> air and every device on a BSSID shares the same group key for encryption, 
>> any client can decode any multicast packet, including RAs not on the same 
>> VLAN.  Again, this is expected behavior.  The solution to this is to use 
>> multicast to unicast conversion for the RA, however i've never done this in 
>> a flexconnect deployment.
>> 
>> This is also important in IPv4 deployments where you need to secure who can 
>> gain access to a multicast stream.
>> 
>>> On Wed, Mar 18, 2015 at 10:32 AM, Frans Panken <[email protected]> 
>>> wrote:
>>> We use FlexConnect in both central and local switched mode (v 8.110.6).
>>> We use a single SSID and distinguish various user groups, differentiated
>>> by Radius and mapped on different VLANs.
>>> We observe that VLANs leak traffic to other VLANs. This is in particular
>>> very undesired with IPv6, where router adverstisements from one VLAN is
>>> broadcast to other VLANs (this also happens on IPv4, e.g., with ARP and
>>> other broadcast traffic). Even VLANs that are only centrally accessible
>>> leak traffic to local VLANs.
>>> 
>>> This is a security issue that in my oppinion does not receive the
>>> desired attention.
>>> 
>>> Frans
>>> 
>>> 
>>> 
>>> Watters, John schreef op 18/03/15 om 07:29:
>>> > Please post any results you have if/when try expand FlexConnect to your 
>>> > entire campus. It looks like you are close to our size (we now have about 
>>> > 125 buildings & about 38K students plus about 4K faculty/staff).
>>> >
>>> > Thanks.
>>> >
>>> > Sent from my iPhone
>>> >
>>> >> On Mar 17, 2015, at 4:12 PM, Hector J Rios <[email protected]> wrote:
>>> >>
>>> >> I've not performed tests to that scale yet. Plus we are only considering 
>>> >> this for our ResHalls, of which we have 21 buildings only.
>>> >>
>>> >> -Hector
>>> >>
>>> >>
>>> >> -----Original Message-----
>>> >> From: The EDUCAUSE Wireless Issues Constituent Group Listserv 
>>> >> [mailto:[email protected]] On Behalf Of Watters, John
>>> >> Sent: Tuesday, March 17, 2015 11:55 AM
>>> >> To: [email protected]
>>> >> Subject: Re: [WIRELESS-LAN] ResHall Wireless - FlexConnect
>>> >>
>>> >> We played with FlexConnect for a number of months but still could not 
>>> >> get what we needed it to do on a consistent basis. Essentially we wanted 
>>> >> FlexConnect to drop users into their building VLAN so they would be able 
>>> >> to easily interact with the same devices that the wired connections in 
>>> >> the buildings could see. As I'm sure you know, this also resolves many 
>>> >> of the Apple, Chromecast, etc., problems.
>>> >>
>>> >> We did have one caveat though that we just couldn't get past -- we 
>>> >> wanted to drop faculty/staff into one VLAN and students into another (we 
>>> >> can easily return the proper VLAN for a particular client in a 
>>> >> particular building from Radius server - FreeRadius with a call to our 
>>> >> LDAP server for info) but  we also need to send everything else back to 
>>> >> the controller for central switching (e.g., police connections, special 
>>> >> bar-code scanners that roam and serve to identify a user, but not being 
>>> >> used for client traffic, for example, to give out free flu shots to 
>>> >> eligible folks or let folks into a sporting event). We just couldn't get 
>>> >> past having 95+% locally switched and the remainder centrally switched 
>>> >> for over 200 buildings many with now over 100 APs each without using 
>>> >> FlecConnect groups which are limited to numbers way too small for our 
>>> >> campus.
>>> >>
>>> >> We can even live comfortably without roaming between buildings. MOst 
>>> >> folks are not used to being able to roam between buildings downtown or 
>>> >> many cannot roam between apartments off campus.
>>> >>
>>> >> How did you get around the FlexConnect group problem?
>>> >>
>>> >>
>>> >>
>>> >>
>>> >> ==========================
>>> >> -jcw
>>> >> ________________________________
>>> >> From: The EDUCAUSE Wireless Issues Constituent Group Listserv 
>>> >> [[email protected]] on behalf of Hector J Rios 
>>> >> [[email protected]]
>>> >> Sent: Tuesday, March 17, 2015 9:27 AM
>>> >> To: [email protected]
>>> >> Subject: Re: [WIRELESS-LAN] ResHall Wireless
>>> >>
>>> >> I tested FlexConnect on 8.0.110.0. Here are my observations:
>>> >>
>>> >> *Great alternative to switch data locally (obviously) *No AVC Support 
>>> >> *When controller is down, AP goes into standalone more. Must make sure 
>>> >> that AP is not able to reach any other controller you don't want. This 
>>> >> was fixed with an ACL.
>>> >> *Client details page does not show client IPv6 address. Client still 
>>> >> gets IPv6 address. (PRIME does show it if you run a report).
>>> >> *Client details page does not show VLAN ID.
>>> >> *Putting AP in FlexConnect mode does not require reboot (Cool!) *No IPv6 
>>> >> ACL support
>>> >>
>>> >> More testing to do, but so far so good.
>>> >>
>>> >> -Hector
>>> >>
>>> >>
>>> >>
>>> >> From: The EDUCAUSE Wireless Issues Constituent Group Listserv 
>>> >> [mailto:[email protected]] On Behalf Of Hector J Rios
>>> >> Sent: Thursday, March 12, 2015 11:13 PM
>>> >> To: [email protected]
>>> >> Subject: Re: [WIRELESS-LAN] ResHall Wireless
>>> >>
>>> >> We use Cisco's wireless solution with WiSM2s and a variety of WAPs. We 
>>> >> actually implemented the guest anchor controller solution last year with 
>>> >> dual controllers (WLC2504) and we've been happy.
>>> >>
>>> >> I like Britton's idea of using FlexConnect at the dorms to switch the 
>>> >> student data locally. However, I believe there are some limitations that 
>>> >> would keep us from using it such as no support for AVC, and some 
>>> >> limitations on IPv6.
>>> >>
>>> >> -Hector
>>> >>
>>> >> From: The EDUCAUSE Wireless Issues Constituent Group Listserv 
>>> >> [mailto:[email protected]] On Behalf Of Osborne, Bruce 
>>> >> W (Network Services)
>>> >> Sent: Thursday, March 12, 2015 7:42 AM
>>> >> To: 
>>> >> [email protected]<mailto:[email protected]>
>>> >> Subject: Re: [WIRELESS-LAN] ResHall Wireless
>>> >>
>>> >> Hector,
>>> >>
>>> >> You do not say what wireless solution you are using. Let me assume a 
>>> >> Cisco or Aruba controller based solution. You can have vlans from your 
>>> >> controller tunnel to an anchor controller in a DMZ.  Use 802.1X 
>>> >> authentication based on AD groups.
>>> >>
>>> >> This solution permits controlled internal access and, if you desire, 
>>> >> unfiltered Internet access. Until recently, we did something similar 
>>> >> with our open Guest wireless network on our Aruba system. We now use a 
>>> >> different solution for this.
>>> >>
>>> >> The anchor controller idea was based on Cisco wireless training several 
>>> >> years ago. At that time, it was their recommended guest solution.
>>> >>
>>> >> Bruce Osborne
>>> >> Wireless Engineer
>>> >> IT Infrastructure & Media Solutions
>>> >>
>>> >> (434) 592-4229
>>> >>
>>> >> LIBERTY UNIVERSITY
>>> >> Training Champions for Christ since 1971
>>> >>
>>> >> From: Hector J Rios [mailto:[email protected]]
>>> >> Sent: Wednesday, March 11, 2015 9:48 AM
>>> >> Subject: ResHall Wireless
>>> >>
>>> >> I'm wondering how many of you treat the wireless in the ResHalls 
>>> >> differently from the wireless on the rest of your campus. In terms of 
>>> >> geography, we have 21 ResHalls that are in the perimeter of our campus. 
>>> >> Some of these buildings are next to academic or administrative 
>>> >> buildings. Eduroam is our main SSID. So, for the longest time it has 
>>> >> only made sense to broadcast eduroam everywhere. Now, on the wired side 
>>> >> of the house, our ResHalls have a dedicated connection that gives them 
>>> >> direct, non-firewall access to the internet (for access to campus 
>>> >> resources, a student must VPN). This came about as a request from the 
>>> >> students to have more freedom in their residence. Makes sense. But 
>>> >> wireless is different as it goes through our campus core, traverses our 
>>> >> perimeter firewall, and goes out our main internet connection.
>>> >>
>>> >> I've struggled to find an alternative solution to this. We recognize 
>>> >> that students in ResHalls are different in the sense that they pay for a 
>>> >> place to live and should get an internet service that is similar to 
>>> >> their home service. However, any alternatives that we have considered 
>>> >> (separate SSID, dynamic VLAN assignment, user groups) just seem to 
>>> >> complicate the setup.
>>> >>
>>> >> Any good ideas out there or creative ways in which you have tackled this 
>>> >> challenge?
>>> >>
>>> >> Thanks,
>>> >>
>>> >> Hector Rios, CCNP, CCA
>>> >> Assistant Director, Network Engineering
>>> >> Dept. of Networking and Infrastructure
>>> >> Information Technology Services
>>> >> Louisiana State University
>>> >>
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