We have two connections at our main NOC, a 2Mb/s SDSL and a 1Mb/s Cable connection we use as a backup. Our SDSL provider has decided that they are going to block all outbound port 25 traffic not destined for their SMTP server in an effort to "protect" people from viruses with built-in SMTP engines.

My short term solution has been to cut everybody over to the backup connection, but this is not a desirable full-time option. So what I want to do is direct all SMTP & POP3 traffic (ports 25 & 110) out the Cable gateway while everything else goes out on the SDSL.

FYI, I typically use WinBox for most routine configuration changes and monitoring, but CL is just as good.

Thanks!

Sir William

You should take a look into the policy routing features of RouterOS. You could mark SMTP/POP3 connections and then route them over the Cable connection.
As you have not given more details, there might be some configuration involved regarding NAT or something else, but this should be the direction to go...

Well, what I've tried so far has been unsuccessful, so I'll give some more details and ask for help.

All local customer traffic is in 10.x.x.x blocks. I have two outbound connections on different interfaces named "SDSL" & "Cable".

I'm using SNAT masquerading for 0.0.0.0/0 to 0.0.0.0/0 out SDSL.

I thought I should be able to do a SNAT masq for 0.0.0.0/8:25 out Cable. But that doesn't work. I tried 10.0.0.0/8:25 also....no luck.

Should I be doing something different to make this work? I just don't know. What I do know is that I HAVE to make it work and SOON.

Try placeing masq rule 10.0.0.0/8:25 before 10.0.0.0/8 it should work

Sir William,

You want 0.0.0.0/0:25, not 0.0.0.0/8:25

so use a dst-address of 0.0.0.0/0:25