nanog mailing list archives
Re: two interfaces one subnet
From: Chris Meidinger <cmeidinger () sendmail com>
Date: Mon, 11 May 2009 23:49:22 +0200
On 11.05.2009, at 23:42, Kevin Oberman wrote:
Date: Mon, 11 May 2009 16:19:56 -0500 From: "Alex H. Ryu" <r.hyunseog () ieee org>Unless you configure Layer 2 for two interfaces, it's not going to work.It is invalid from networking principle.If you have to send the traffic for host in same subnet you configured,which interface it should send out ?Basically it may create broadcast storm loop by putting two ip addressesin same subnet in different interface. It may be allowed from host-level, but from router equipment, I don't think it was allowed at all. AlexI am a bit baffled as to why people think: 1. It won't work 2. It is a bad thing to do if it would work Neither is true. If it is two separate interfaces with two MACaddresses, it will work fine IF one of the interfaces is configured witha netmask of 255.255.255.255 (/32). Of course, you will have to addroutes for the second interface if you expect to source traffic from it,but it really in not rare.
This is, of course, how I've done it at times in the past. Routing management can, however, become quite a pain over time.
The customer expectation is, naturally, that any traffic related to a connection that comes in to the first interface should go back out that interface, and anything related to a connection that came into the second interface should go back out there. (All this without any specific routing etc.)
I think we both know that that's not going to happen automagically. Chris
Current thread:
- Re: two interfaces one subnet, (continued)
- Re: two interfaces one subnet Mikael Abrahamsson (May 11)
- Re: two interfaces one subnet Duane Waddle (May 11)
- Re: two interfaces one subnet Daryl G. Jurbala (May 12)
- Re: two interfaces one subnet Charles Wyble (May 11)
- Re: two interfaces one subnet Chris Meidinger (May 11)
- Re: two interfaces one subnet Nathan Ward (May 11)
- Re: two interfaces one subnet Duane Waddle (May 11)
- Re: two interfaces one subnet Alex H. Ryu (May 11)
- Re: two interfaces one subnet Chris Meidinger (May 11)
- Re: two interfaces one subnet Brielle Bruns (May 11)
- Re: two interfaces one subnet Kevin Oberman (May 11)
- Re: two interfaces one subnet Chris Meidinger (May 11)
- Re: two interfaces one subnet Patrick W. Gilmore (May 11)
- Re: two interfaces one subnet Arnold Nipper (May 11)
- Re: two interfaces one subnet Patrick W. Gilmore (May 11)
- Re: two interfaces one subnet Arnold Nipper (May 11)
- Re: two interfaces one subnet Patrick W. Gilmore (May 11)
- Re: two interfaces one subnet Chris Meidinger (May 11)
- Re: two interfaces one subnet Mikael Abrahamsson (May 11)
- Re: two interfaces one subnet Hector Herrera (May 11)
- Re: two interfaces one subnet Ben Scott (May 11)
- Re: two interfaces one subnet Patrick W. Gilmore (May 11)
- Re: two interfaces one subnet Ben Scott (May 11)