Cable Modem ISP Blocking Ports for Apache & Postfix

[johnsi]

It appears my Cable ISP is blocking Ports 80 and 25 to combat the Code Red Worm. Why Port 25, I do not know. I validated this by trying to Telnet to these ports from a dial-up ISP.

I'm running Mandrake 7.1 with Apache and Postfix servers. I was able to fix Apache by changing to port 8080 in the httpd.conf file and then changing my DNS Service via port forwarding.

However, I'm cannot figure out how to change postfix to another port. As I understand it, smtp always uses port 25 on the client and server to transfer mail. If I can change postfix to listen on another port, how would I get an email to someone@xxxx.com to be forwarded to the right port. Would I have to change the port forwarding to xxxx.com to the new port address I assigned postfix?

[posterboy]

Oh, really? What cable ISP has done that? Man, what a bummer. I have AT&T and went the same route you did, with dns2go which redirects the port to avoid 80. Now, if you can find a way, maybe you could redirect mail.domain.com someplace else, exactly as www.domain.com. (http://www.domain.com.) I look for AT&T to follow suit, soon. Ray

[johnsi]

Cox@home is my ISP. I use a pay for DNS service ($25/year), Dynu, and they claim they're working on a solution to reroute inbound port 25 packets. I think amatuers like myself who have dsl or cable modem and want to have their own web servers, etc. are a good chunk of their business. So I think they are motivated.

I still need to figure out how to get postfix to listen for smtp packets on another port. However, I think I've seen several potential solutions in this and other forums.

[posterboy]

Yes, that can surely be done. I am re-routing my www addy with a dns service, to get around the blocked port 80 issue. The thing with mail is going to be the added word in your address, ie: ray@mail.raymondjones.net, which I am not going to like. Oh, well.
Ray

[posterboy]

[Craig McPherson]

If you run your SMTP server on a non-standard port, you'll be able to use it to SEND mail (anal firewalls on remote mailservers might cause problems, though), but not to RECEIVE mail. If you have your SMTP server running from a superserver, just change your superserver configuration file to run the SMTP server on a different port. It shouldn't complain.

It might be time to consider a new ISP. Can you get DSL in your area? Most DSL providers are a bit less anal about servers than the average cable provider, and some like Speakeasy are downright friendly. All I can get in my area is Southwestern Bell DSL, but they have a decent "do what you like, just don't expect us to troubleshoot your private network" policy.