A dual WAN router for session-persistent connections

[shivan82]

Hello all, I'm new here!

I've got a mail server that I would like to setup to use two gateways, one WAN link is an ADSL connection with 4mb download/512kupload which I want to use for receiving mail, the other link, a costly serial connection with 2mb upload bandwidth, I want to use for sending mail(all SMTP over port 25). Setting up a dual gateway with Windows and getting it to stick to one gateway per TCP session pretty much impossible. I want to save precious upload bandwidth by using the cheap ADSL link for incoming mail.

I need some advice on a tried and tested dual WAN router that will stick to one WAN link per session, session-persistent(both incoming/outgoing), has anyone had this same issue? I can't setup static routes of course, because I don't know who will be sending me mail.


Thanks in advance for all replies.

[ErikD]

How does downloading email hurt the upload of the serial link? If it is a symetrical link than it should be 2Mb up and down, so donloading and uploading over it won't hurt the bandwidth at all.

What are you currently using as a router? My first though would be like an ACL or route map.

[shivan82]

Well the 2mb link is being used for much more than just mail sending, so I'd like to save it as much as possible.

I've heard peplink is a good brand, just a bit pricey, any other ideas?

[ErikD]

Never heard of that brand. I think for such a complex setup you might very well need to go with hardware from Cisco or Juniper. I know Linksys makes some business grade dual WAN routers, but am not to sure if they will allow you to specify which connection is used for what.

What about load balancing? That might be an easier way to go.

[YeOldeStonecat]

I know Linksys makes some business grade dual WAN routers, but am not to sure if they will allow you to specify which connection is used for what.

Yes the RV0 series, when set in load balance mode, you can bind protocols to specific WAN ports.

[greEd]

Although you can segment the protocols, why not just prioritize the traffic?

I use OpenBSD for this purpose:
http://www.openbsd.org/faq/pf/queueing.html

Scroll down to the bottom of the document and with the exception of the firewall having one interface, and the WWW being in the DMZ you could just as easily replace this setup with your mail server / dual wan setup.

If you use OpenBSD you can also setup which interfaces to use for what purpose, not that you can't do this with higher end routers, just offering a alternative.