Multiple network interface routing issue

Multiple network interface routing issue

Post by Richard N » Wed, 14 Aug 2002 06:18:46



See if anybody have the answer for this issue:

We have a RS/6000 server with 3 network interface, en0(205.239.71.15)
and en2 (205.239.71.51) are on the same network, en1 is on another
network I am not interested.
#netstat -rn
Routing tables
Destination      Gateway           Flags   Refs     Use  If   PMTU
Exp  Groups

Route Tree for Protocol Family 2 (Internet):
default          205.239.71.1      UG        0      371  en0     -   -
100.1.1/24       100.1.1.2         U         0        0  en1     -   -
127/8            127.0.0.1         U         9      823  lo0     -   -
205.239.71/24    205.239.71.15     U         6  7077735  en0     -   -

Route Tree for Protocol Family 24 (Internet v6):
::1              ::1               UH        0        0  lo0 16896   -

All external accesses from this machine will have an identity of
205.239.71.15, such as FTP. But for certain external restriction, some
ftp sessions are only allowed to IP 205.239.71.51, that is the IP for
en2. So my ftp will fail because the remote site will deny the IP
205.239.71.15.
A simple idea will be change the en0 IP to 205.239.71.51, which I
don't want to do because of some other issues.

I then tried the below:
#route delete -net 205.239.71.0 205.239.71.15
#route add -net 205.239.71.0 205.239.71.51 -interface

#netstat -rn
Routing tables
Destination      Gateway           Flags   Refs     Use  If   PMTU
Exp  Groups

Route Tree for Protocol Family 2 (Internet):
default          205.239.71.1      UG        0      371  en0     -   -
100.1.1/24       100.1.1.2         U         0        0  en1     -   -
127/8            127.0.0.1         U         9      823  lo0     -   -
205.239.71/24    205.239.71.51     U         6  7077735  en2     -   -

Route Tree for Protocol Family 24 (Internet v6):
::1              ::1               UH        0        0  lo0 16896   -

Seems the routing table has been change to route all traffics through
en2 (205.239.71.51), but ftp still failed as it's identity is still
not changed.

I have no idea, how about you?

 
 
 

Multiple network interface routing issue

Post by Clive Spark » Wed, 14 Aug 2002 16:40:07



> See if anybody have the answer for this issue:

> We have a RS/6000 server with 3 network interface, en0(205.239.71.15)
> and en2 (205.239.71.51) are on the same network, en1 is on another
> network I am not interested.
> #netstat -rn
> Routing tables
> Destination      Gateway           Flags   Refs     Use  If   PMTU
> Exp  Groups

> Route Tree for Protocol Family 2 (Internet):
> default          205.239.71.1      UG        0      371  en0     -   -
> 100.1.1/24       100.1.1.2         U         0        0  en1     -   -
> 127/8            127.0.0.1         U         9      823  lo0     -   -
> 205.239.71/24    205.239.71.15     U         6  7077735  en0     -   -

> Route Tree for Protocol Family 24 (Internet v6):
> ::1              ::1               UH        0        0  lo0 16896   -

> All external accesses from this machine will have an identity of
> 205.239.71.15, such as FTP. But for certain external restriction, some
> ftp sessions are only allowed to IP 205.239.71.51, that is the IP for
> en2. So my ftp will fail because the remote site will deny the IP
> 205.239.71.15.
> A simple idea will be change the en0 IP to 205.239.71.51, which I
> don't want to do because of some other issues.

> I then tried the below:
> #route delete -net 205.239.71.0 205.239.71.15
> #route add -net 205.239.71.0 205.239.71.51 -interface

> #netstat -rn
> Routing tables
> Destination      Gateway           Flags   Refs     Use  If   PMTU
> Exp  Groups

> Route Tree for Protocol Family 2 (Internet):
> default          205.239.71.1      UG        0      371  en0     -   -
> 100.1.1/24       100.1.1.2         U         0        0  en1     -   -
> 127/8            127.0.0.1         U         9      823  lo0     -   -
> 205.239.71/24    205.239.71.51     U         6  7077735  en2     -   -

> Route Tree for Protocol Family 24 (Internet v6):
> ::1              ::1               UH        0        0  lo0 16896   -

> Seems the routing table has been change to route all traffics through
> en2 (205.239.71.51), but ftp still failed as it's identity is still
> not changed.

> I have no idea, how about you?

The default route is still via en0, is the ftp target also in the
205.239.71/24 network?

Suggest you try a traceroute to the target system.

--
Regards,
Clive

 
 
 

Multiple network interface routing issue

Post by Richard N » Thu, 15 Aug 2002 02:50:28


Yeah, the default route is still through en0. I will try delete the
default route and add it again.
 
 
 

Multiple network interface routing issue

Post by Claude Wats » Thu, 15 Aug 2002 11:19:46


        Why not just alias 205.239.71.51 to en0?  You can do that
easily enough through SMIT.  I'm fairly confident that two interfaces
on the same network segment will never give you anything but the
results you are seeing now.  It will always take the first one found.

Claude Watson



Quote:>See if anybody have the answer for this issue:

>We have a RS/6000 server with 3 network interface, en0(205.239.71.15)
>and en2 (205.239.71.51) are on the same network, en1 is on another
>network I am not interested.
>#netstat -rn
>Routing tables
>Destination      Gateway           Flags   Refs     Use  If   PMTU
>Exp  Groups

>Route Tree for Protocol Family 2 (Internet):
>default          205.239.71.1      UG        0      371  en0     -   -
>100.1.1/24       100.1.1.2         U         0        0  en1     -   -
>127/8            127.0.0.1         U         9      823  lo0     -   -
>205.239.71/24    205.239.71.15     U         6  7077735  en0     -   -

>Route Tree for Protocol Family 24 (Internet v6):
>::1              ::1               UH        0        0  lo0 16896   -

>All external accesses from this machine will have an identity of
>205.239.71.15, such as FTP. But for certain external restriction, some
>ftp sessions are only allowed to IP 205.239.71.51, that is the IP for
>en2. So my ftp will fail because the remote site will deny the IP
>205.239.71.15.
>A simple idea will be change the en0 IP to 205.239.71.51, which I
>don't want to do because of some other issues.

>I then tried the below:
>#route delete -net 205.239.71.0 205.239.71.15
>#route add -net 205.239.71.0 205.239.71.51 -interface

>#netstat -rn
>Routing tables
>Destination      Gateway           Flags   Refs     Use  If   PMTU
>Exp  Groups

>Route Tree for Protocol Family 2 (Internet):
>default          205.239.71.1      UG        0      371  en0     -   -
>100.1.1/24       100.1.1.2         U         0        0  en1     -   -
>127/8            127.0.0.1         U         9      823  lo0     -   -
>205.239.71/24    205.239.71.51     U         6  7077735  en2     -   -

>Route Tree for Protocol Family 24 (Internet v6):
>::1              ::1               UH        0        0  lo0 16896   -

>Seems the routing table has been change to route all traffics through
>en2 (205.239.71.51), but ftp still failed as it's identity is still
>not changed.

>I have no idea, how about you?

 
 
 

Multiple network interface routing issue

Post by Clive Spark » Thu, 15 Aug 2002 16:59:04



> Yeah, the default route is still through en0. I will try delete the
> default route and add it again.

It might be better to set up a specific static route to your ftp
target via en2.

Also to ensure the route survives a reboot it should be added to the
odm.  Rather than using route add/delete etc, use the smit screens
'mkroute' & 'rmroute'

--
Regards,
Clive

 
 
 

1. Routing Issue with Multiple PPP interfaces

Hello Everyone.

I have Redhat 6.2 acting as a file server / internet gateway for a small
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My problem is that I want to bring up both ppp interfaces ; ppp0  and ppp1
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