Routing Issue with Multiple PPP interfaces

Routing Issue with Multiple PPP interfaces

Post by <s.how.. » Tue, 31 Jul 2001 14:07:09



Hello Everyone.

I have Redhat 6.2 acting as a file server / internet gateway for a small
office network , with 2 modems attached ( one for dial-in , and the other
for dial out). All works fine.

My problem is that I want to bring up both ppp interfaces ; ppp0  and ppp1
for outgoing connections to 2 different ISP's
(no problem with this), BUT, I want to be able to route ip packets from one
particular workstation to the ppp1
interface exclusively so that I dont exceed download  / time limits on the
ISP that ppp0 is connected to.

The route command appearas to only worry about destinations -- no way of
specifying the souce of the Ip packets;
IPCHAINS has a -i (interface) option , but is this for routing purposes or
is it only a specification to determine if that rule applies in the chain ?

Can any one give me pointers to acheiving this situation?

Many Thanks

Scott Howard

 
 
 

Routing Issue with Multiple PPP interfaces

Post by Dean Thompso » Tue, 31 Jul 2001 16:12:40


Hi!,

Quote:> I have Redhat 6.2 acting as a file server / internet gateway for a small
> office network , with 2 modems attached ( one for dial-in , and the other
> for dial out). All works fine.

> My problem is that I want to bring up both ppp interfaces ; ppp0  and ppp1
> for outgoing connections to 2 different ISP's
> (no problem with this), BUT, I want to be able to route ip packets from one
> particular workstation to the ppp1
> interface exclusively so that I dont exceed download  / time limits on the
> ISP that ppp0 is connected to.

> The route command appearas to only worry about destinations -- no way of
> specifying the souce of the Ip packets;
> IPCHAINS has a -i (interface) option , but is this for routing purposes or
> is it only a specification to determine if that rule applies in the chain ?

> Can any one give me pointers to acheiving this situation?

I would have thought that iptables might have been able to provide some of a
solution here, but as you are running Redhat 6.2 and most likely not using the
new kernel, this isn't an option.

I am not sure whether it can be done or not, but you might like to take a look
at the iproute2 package and see whether or not you can specify more control
over your routing tables with its commands.

You should be able to find iproute2 on http://www.rpmfind.net or failing that,
a quick search on http://www.google.com should be able to provide you with a
number of points to locate the package.

See ya

Dean Thompson

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Routing Issue with Multiple PPP interfaces

Post by Bill Unr » Wed, 01 Aug 2001 02:02:11


]I have Redhat 6.2 acting as a file server / internet gateway for a small
]office network , with 2 modems attached ( one for dial-in , and the other
]for dial out). All works fine.

]My problem is that I want to bring up both ppp interfaces ; ppp0  and ppp1
]for outgoing connections to 2 different ISP's

You only have one modem for outgoing. One modem means one interface.
One modem cannot dial two separate ISPs. Please clarify what you are
doing. Or is your above description wrong and you use both modems for
dialout?

](no problem with this), BUT, I want to be able to route ip packets from one
]particular workstation to the ppp1
]interface exclusively so that I dont exceed download  / time limits on the
]ISP that ppp0 is connected to.

You might be able to do this with outgoing packets (see the source
routing response) but that does not mean that incoming packets will
follow the same route. You are as liable to get all ofthe incoming
packets coming down only one of the lines.

 
 
 

1. Multiple network interface routing issue

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?

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