CentOS - Aug 2013 - Two external interfaces, one with "default" route and ping problem

Hi

I have two different IP addresses (in a block of /29), one is on port 0 and the
other is on port 2 of a Ciso 888.
I am doing this so I can have two different certs with two different ip
addresses.

I have tried:

 1) one machine, two real interfaces, two cables (eth0 and eth2)
 2) one machine, one real interface eth0 and one virtual interface eth0:1, one
network cable


Using number 2)
I can ping the two different ip addresses, no problem. The only problem here is
that iptables does not work (I cannot create rules for eth0:1 - and yes I know
about the security implications).


I have a problem with number number 1)

I can ping the first ip address and I get a return, but I cannot get a return
when I ping the second ip address.
I can see traffic coming into the second interface but it does not return.
Now one of the interfaces needs the "default" route applied (is this
correct??), which is eth0.

I assume this is a routing problem?
What do I need to do to get this to work?



Jobst







-- 
Student to Teacher: Sir, what's an oxymoron? .... Teacher to Student:
"Microsoft Works".

  | |0| |   Jobst Schmalenbach, jobst at barrett.com.au, General Manager
  | | |0|   Barrett Consulting Group P/L & The Meditation Room P/L
  |0|0|0|   +61 3 9532 7677, POBox 277, Caulfield South, 3162, Australia

Hi,

Two IP addresses within the same subnet is generally something that should
be avoided if at all possible.

See
http://serverfault.com/questions/336021/two-network-interfaces-and-two-ip-addresses-on-the-same-subnet-in-linuxfor
some information that may help.




On Tue, Aug 20, 2013 at 3:41 PM, Jobst Schmalenbach <jobst at
barrett.com.au>wrote:
>
> Hi
>
> I have two different IP addresses (in a block of /29), one is on port 0
> and the other is on port 2 of a Ciso 888.
> I am doing this so I can have two different certs with two different ip
> addresses.
>
> I have tried:
>
>  1) one machine, two real interfaces, two cables (eth0 and eth2)
>  2) one machine, one real interface eth0 and one virtual interface eth0:1,
> one network cable
>
>
> Using number 2)
> I can ping the two different ip addresses, no problem. The only problem
> here is that iptables does not work (I cannot create rules for eth0:1 - and
> yes I know about the security implications).
>
>
> I have a problem with number number 1)
>
> I can ping the first ip address and I get a return, but I cannot get a
> return when I ping the second ip address.
> I can see traffic coming into the second interface but it does not return.
> Now one of the interfaces needs the "default" route applied (is
this
> correct??), which is eth0.
>
> I assume this is a routing problem?
> What do I need to do to get this to work?
>
>
>
> Jobst
>
>
>
>
>
>
>
> --
> Student to Teacher: Sir, what's an oxymoron? .... Teacher to Student:
> "Microsoft Works".
>
>   | |0| |   Jobst Schmalenbach, jobst at barrett.com.au, General Manager
>   | | |0|   Barrett Consulting Group P/L & The Meditation Room P/L
>   |0|0|0|   +61 3 9532 7677, POBox 277, Caulfield South, 3162, Australia
> _______________________________________________
> CentOS mailing list
> CentOS at centos.org
> http://lists.centos.org/mailman/listinfo/centos
>

On Mon, Aug 19, 2013 at 10:41 PM, Jobst Schmalenbach
<jobst at barrett.com.au> wrote:
>
> Hi
>
> I have two different IP addresses (in a block of /29), one is on port 0 and
the other is on port 2 of a Ciso 888.
> I am doing this so I can have two different certs with two different ip
addresses.
>
> I have tried:
>
>  1) one machine, two real interfaces, two cables (eth0 and eth2)
>  2) one machine, one real interface eth0 and one virtual interface eth0:1,
one network cable
>
>
> Using number 2)
> I can ping the two different ip addresses, no problem. The only problem
here is that iptables does not work (I cannot create rules for eth0:1 - and yes
I know about the security implications).
Why do you need different rules for eth0:1?  Can't you specify the IP
addresses?

-- 
   Les Mikesell
    lesmikesell at gmail.com