Postfix behind a proxy

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Swift-wp

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Hi Guys

I need some help. I'm struggling to get postfix to send mail through the proxy server. When I send it from an ADSL line it works fine, but through the campus proxy it doesn't want to work.
 
Usually the proxy in place is web filtering, and there may be no default gateway address set up on the individual computers' TCP/IP address, so you cannot get direct access to the internet. It's what I do at work to stop people getting net access for anything but internet.

Unless the campus is running ISA server or some other high end thing, they can't open up port 25 fro sending out mail, and that is the end of that.

Also, mail sent through proxies are usually classified as spam by most spam filters AFAIK.
 
Ok I got the thing to send mail. Been away from work for a week. I added the university's smtp server as the relayhost, but now it won't deliver mail to an external email address, i.e. an email ddress without the uwc.ac.za domain. Can someone give me feedback on this please.
 
Swift-wp said:
Ok I got the thing to send mail. Been away from work for a week. I added the university's smtp server as the relayhost, but now it won't deliver mail to an external email address, i.e. an email ddress without the uwc.ac.za domain. Can someone give me feedback on this please.
Click to expand...

perhaps the university's smtp server which you're using as a relay, requires authentication for mail outside of the local domains it handles?

It sounds like the problem, since the server probably has a 'allow from same network' rule which disregards authentication for local mail but then doesn't allow 'external' mail without authentication, since it would then be acting as a open smtp relay server subject to quite a bit of abuse.

are you by chance able to access either the SAIX or IS smtps, and then just use them as a relay?
 
Swift-wp said:
Hi Guys

I need some help. I'm struggling to get postfix to send mail through the proxy server. When I send it from an ADSL line it works fine, but through the campus proxy it doesn't want to work.
Click to expand...

No really - you can't.

A proxy is for web traffic. Postfix is SMTP.

No firewall admin in their right mind would allow the proxy server to talk out on port 25. Mostly likely they only allow 21,80 and 443
 
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