Re: [c-nsp] IP helper-address source from loopback?
Jay, Take a look here... I think this should do the trick. http://www.cisco.com/en/US/docs/ios/ipaddr/configuration/guide/iad_dhcps ervidlink_mcp.html#wp1058967 Arie -Original Message- From: cisco-nsp-boun...@puck.nether.net [mailto:cisco-nsp-boun...@puck.nether.net] On Behalf Of Jay Hennigan Sent: Tuesday, March 20, 2012 07:37 To: cisco-nsp@puck.nether.net Subject: [c-nsp] IP helper-address source from loopback? We have a setup where an external global DHCP server is used to assign pools within a few VRFs on 7206VXR, IOS 12.4. Interface configuration looks like this: interface Port-channel1.3004 description Test encapsulation dot1Q 3004 ip vrf forwarding net21 ip address 10.21.97.126 255.255.255.192 ip helper-address global w.x.y.z We're using option 82 to communicate the vrf subnet information and it all works well. The problem that I'm trying to solve is to use a loopback as the global source interface from which the DHCP requests originate. With the above configuration the router uses the closest egress interface to the DHCP server. This is quite usable but I'd prefer it originate on a loopback for cleanliness and redundancy. IOS has tweaks to manipulate the source address of telnet, RADIUS, ftp, tftp, rcmd, and the like but I don't see an obvious way to specify the source of the DHCP relay packets. I'm considering attempting a local route-map as a possible solution but that seems like a pretty big hammer for a small tweak if it works at all. Any suggestions from the assorted Cisco wizards? -- Jay Hennigan - CCIE #7880 - Network Engineering - j...@impulse.net Impulse Internet Service - http://www.impulse.net/ Your local telephone and internet company - 805 884-6323 - WB6RDV ___ cisco-nsp mailing list cisco-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/ ___ cisco-nsp mailing list cisco-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
Re: [c-nsp] IP helper-address source from loopback?
On 3/19/12 11:56 PM, Arie Vayner (avayner) wrote: Jay, Take a look here... I think this should do the trick. http://www.cisco.com/en/US/docs/ios/ipaddr/configuration/guide/iad_dhcps ervidlink_mcp.html#wp1058967 Arie It indeed does! It's only in the SE train, so now I need to analyze how much I want this and what might break... -- Jay Hennigan - CCIE #7880 - Network Engineering - j...@impulse.net Impulse Internet Service - http://www.impulse.net/ Your local telephone and internet company - 805 884-6323 - WB6RDV ___ cisco-nsp mailing list cisco-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
[c-nsp] IP helper-address source from loopback?
We have a setup where an external global DHCP server is used to assign pools within a few VRFs on 7206VXR, IOS 12.4. Interface configuration looks like this: interface Port-channel1.3004 description Test encapsulation dot1Q 3004 ip vrf forwarding net21 ip address 10.21.97.126 255.255.255.192 ip helper-address global w.x.y.z We're using option 82 to communicate the vrf subnet information and it all works well. The problem that I'm trying to solve is to use a loopback as the global source interface from which the DHCP requests originate. With the above configuration the router uses the closest egress interface to the DHCP server. This is quite usable but I'd prefer it originate on a loopback for cleanliness and redundancy. IOS has tweaks to manipulate the source address of telnet, RADIUS, ftp, tftp, rcmd, and the like but I don't see an obvious way to specify the source of the DHCP relay packets. I'm considering attempting a local route-map as a possible solution but that seems like a pretty big hammer for a small tweak if it works at all. Any suggestions from the assorted Cisco wizards? -- Jay Hennigan - CCIE #7880 - Network Engineering - j...@impulse.net Impulse Internet Service - http://www.impulse.net/ Your local telephone and internet company - 805 884-6323 - WB6RDV ___ cisco-nsp mailing list cisco-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
