Email server problem - Sending email from remote host.

[smakme7757]

My initial setup was as follows:

1x Server with Postfix using ISP smart host and Courier Email - Port 25 and 143

What Worked:
*IMAP - both remote and local
*Receiving Email - both remote and local
*Sending email from localhost
*Sending email from another machines on the same internal network
*telnet from localhost or local machine on port 25

What didn't work
*Sending email from a remote host
*telnet into server on port 25 from remote host

Current setup that works:

1x Server with postfix using smart host - Port 587 (For sending Email)
1x Server with Postfix and Courier IMAP - Port 25 (For receiving email)

So to be able to send email or to connect to my server with telnet i had to use a port other than port 25.

What baffles me is that I've always been able to receive email on port 25, so why couldn't i log in remotely on port 25 or use it to relay email?

My guess is that the ISP catches everything on port 25. If it's an Email it send it through to my address. If it isn't then it just drops the packets?

Could it be something like this?

Thanks

 

[bobross419]

There are a lot of ISPs that block port 25 traffic these days. Enabling submissions (587) on postfix usually works around this. You should be able to do this on just one server though.

 

[smakme7757]

it turned that the place i was trouble shooting from blocked port 25 :/.

also i did figure out how to use port 587 on The same postfix server without needing a second server, so not a complete waste of time

thanks for the response.