[SUMMARY]: How can we make a multihomed server replying on the same interface

From: Dirk Maass <dm_at_hejoe.de>
Date: Fri Sep 24 2004 - 04:30:51 EDT
Dirk Maass wrote:
 > Is there a way to make that the server sends his answer packet out on
 > that interface where the request arrived?

Thanks to all of you who replied to my question,
especially to Adam Levin who gave me more insight.

Although I haven't solved my case yet, I want to summarize because all 
answers were the same: NO.

Casper Dik wrote:
> No; the information is lost as soon as the packet arrives so the
> system cannot know where to send it back.

Darren Dunham wrote:
> #2, There's not always a concept of "the answer packet".  Although it
>     makes a lot of sense for NFS, there's nothing that says an input
>     packet has to cause an output packet.  So output can be based on
>     several inputs, and then there's no easy way to align them.
> ...
> My concern is that if you're
> doing UDP, there's no connection, so the sender IP address could be
> different.

Casper and Darren also suggested using NFS over TCP, "but that would 
only address NFS and not the rest" (Casper)

A static host route as Drew Skinner suggested would not solve my sroblem 
as there are many Firewalls not only one. I tried to set up a static 
network route in the server to the network where the Firewalls are 
located. But that didn't help. With tcpdump I still saw server-packets 
from different IP addresses.

Adam helped me to understand that the server would send out the 
UDP-packet on that interface wich it believes it's closest to the 
client. So the solution may also lay in a router/network config and may 
probably result in a simpler network setup.
I'll have to think about it and to discuss the problem deeper with the 
networkers because I have no access to these components here.

Thank you all, again.
sunmanagers mailing list
Received on Fri Sep 24 04:30:41 2004

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