two interfaces one subnet
cmeidinger at sendmail.com
Mon May 11 15:45:53 CDT 2009
On 11.05.2009, at 22:34, Patrick W. Gilmore wrote:
> On May 11, 2009, at 4:29 PM, Chris Meidinger wrote:
>> I would be grateful for a pointer to such an RFC statement,
>> assuming it exists.
> Why would an RFC prohibit this?
> Most _implementations_ do, but as far as network "rules" in general
> it is a valid configuration.
That was essentially my conclusion as well: logically it can't work,
but I wasn't certain where it might be forbidden.
Thusly did I come to NANOG with the question, thinking smarter people
than I might know. If it's completely down to implementation, or
really to the interaction between TCP and underlying IP, then so be
it. I was hoping that I might just not have thought of the right place
On 11.05.2009, at 22:39, Mikael Abrahamsson wrote:
> On Mon, 11 May 2009, Chris Meidinger wrote:
>> I've been looking through RFC's trying to find a clear statement
>> that having two interfaces in the same subnet does not work, but
>> can't find it that statement anywhere.
> I don't know if it still works, but it did in Linux little over 10
> years back. Proxy-arp:ed all the IPs in the /27 in the /24 and
> everything was fine (legacy reasons plus radiolink which I didn't
> want to run a lot of broadcasts over). There are "legitimate" cases
> where you might want to do this.
Yes, I've gotten it to work as well as little as 10 days ago, but it's
not something that $random_customer should be doing as a matter of
Thus, again, my hope that I just wasn't thinking of the right place to
look to find an IETF recommendation against doing so.
Thanks for the input!
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