Routing a network through a second ISP

[jasomo]

Hi all

¿Is it possible to route certain network through a second ISP instead of the default one?
Routing is based on destination so logically that's not the way.

¿Could for example the NAT work for this purpose?

Thx ALL

[northlandboy]

PBR - Policy Based Routing - gives you the option to do source routing, which I think is what you want to do, right?

It depends what OS you are running - you can do it on later versions of IPSO, and with SPLAT Pro, although I don't think you'll get TAC help.

[jasomo]

I PBR is iproute2, i've been trying it.

It seemed to work but not completely.

ICMP are routed without problems.
But when i try to establish a TCP connection, cannot complete the triple handshake:
--> SYN Well routed through the second ISP.
<-- SYN-ACK Received.
--> ACK Routed through the 1st ISP ??!?!?!?!

I just created a routing table.
Added a rule for the network to be routed using that table.
Added a default gateway route on that table.

Am i doing something wrong?

Thx!!

[TommyBoay]

I had a similar issue.. until I disabled SecureXL. could you try the same thing with fwaccel off ? (if the stat shows enabled)

[hotice_]

Originally Posted by TommyBoay

I had a similar issue.. until I disabled SecureXL. could you try the same thing with fwaccel off ? (if the stat shows enabled)

I tried this..still no dice

I'm on R70 no HFA>..never got PBR to work (SPLAT)

[Nico57]

FWIW, I've got it working on R65/splat.

It was pretty straightforward, just took me some time to figure out that source NAT is done after routing.

Basically, I had to type the following commands and add the corresponding NAT rules:
1) ip rule add from <redirected subnet 1> table <x>
2) ip rule add from <redirected subnet 2> table <x>
3) ip route throw <global internal network> table <x>
4) ip route add default <new Internet gw> table <x>

1, 2: use a new routing table, table <x>, instead of the main table, for these 2 subnets
3: switch back to regular routing for internal destinations
4: route external connections to the new Internet gateway