ip alias and default outgoing interface

ip alias and default outgoing interface

[Mohammad A. Haque]

I've got a setup where I have one ethernet card and multiple ips 
assigned using ip alias.

i've noticed that sometimes out going traffic goes out using the ip of 
the last interface I brought up.

Is this supposed to happen? How do I make it so that the default gw 
interface is used?

Thanks

-- 

=====================================================================
Mohammad A. Haque                              http://www.haque.net/ 
                                               mhaque@haque.net

  "Alcohol and calculus don't mix. 
   Don't drink and derive." --Unknown 

=====================================================================

Re: ip alias and default outgoing interface

[Bill Davidsen]

On Wed, 22 May 2002, Mohammad A. Haque wrote:

> I've got a setup where I have one ethernet card and multiple ips 
> assigned using ip alias.
> 
> i've noticed that sometimes out going traffic goes out using the ip of 
> the last interface I brought up.
> 
> Is this supposed to happen? How do I make it so that the default gw 
> interface is used?

Time to tell us which kernel you run. I haven't seen this with 2.4.recent,
but most of the connections are either incoming or explicitly SNET'd.

-- 
bill davidsen <davidsen@tmr.com>
  CTO, TMR Associates, Inc
Doing interesting things with little computers since 1979.

Re: ip alias and default outgoing interface

[Wiktor Wodecki]

[-- Attachment #1: Type: text/plain, Size: 672 bytes --]

On Wed, May 22, 2002 at 12:05:24AM -0400, Mohammad A. Haque wrote:
> I've got a setup where I have one ethernet card and multiple ips 
> assigned using ip alias.
> Is this supposed to happen? How do I make it so that the default gw 
> interface is used?

I've seen similar behaviour with current 2.4 kernels with several nics
with different ip's in one subnet. The solution was to create an own
routing table for each ip (networkcard therefore) and to hammer static
ip-nic arp entries at the router before. Look at the advanced routing
howto for more information or write me a private email.

-- 

Regards,

Wiktor Wodecki <w.wodecki@manfred-dahlhoff.de>

[-- Attachment #2: Type: application/pgp-signature, Size: 240 bytes --]

Re: ip alias and default outgoing interface

[J Sloan]

I'm seeing also - this is with 2.4.19-pre3aa2 -
and I know I saw it with earlier 2.4 kernels.
I just checked and I'm seeing it on my
workstation here, running 2.4.19-pre8-ac5.

I'd have a working ethernet interface, with
a functional default route - now if I bring up
a virtual address on the same ethernet
device, all outgoing traffic from that point
on emanates from the IP of the new virtual
interface - which created some problems
if there are firewall rules based on IP addr.

I know there is some way to fix this with the
advanced routing features, but I hadn't time
to look into it until now - and the above does
seem to be the default behavior.

Joe

Bill Davidsen wrote:

>On Wed, 22 May 2002, Mohammad A. Haque wrote:
>
>  
>
>>I've got a setup where I have one ethernet card and multiple ips 
>>assigned using ip alias.
>>
>>i've noticed that sometimes out going traffic goes out using the ip of 
>>the last interface I brought up.
>>
>>Is this supposed to happen? How do I make it so that the default gw 
>>interface is used?
>>    
>>
>
>Time to tell us which kernel you run. I haven't seen this with 2.4.recent,
>but most of the connections are either incoming or explicitly SNET'd.
>
>  
>