MY ISP is blocking port 25

[egurski]

There are now a large number of ISP's that are starting to block Port 25. This is done to prevent spamming, which is great!!! However, those of you who may have your own domains can run into a problem --- you can receive mail but you cannot send mail through your mail server.

I know some of you may be using sendmail. This is not guaranteed to work for all recipients since ISP's are now perfroming reverse lookups on the senders. They may block it or send a response sayung that at some future date they will no longer accept your e-mails.

The solution:

You need to use your ISP's SMTP server! Now all you need to do is setup so that you are pointing to your ISP's SMTP server, but still use your own doamin name userid. (i.e. me@mydomain and myispsmtp@myiispdoamin)

Here is a link to determine if your ISP is blocking port 25 http://www.kwsonline.com/rcenter/ispconfig.htm

Ed

[JonR]

It can be worth checking that your ISP isn't offering an aternative port - some provide on port 225 for instance...

[jeru]

Probably the most elegent solution/howto would be setting up your own smtp server to relay 'through' the isp's mailgate. This way you can use your own mail server as normal and not worry about configuring multiple "client's" to use somebody elses relay. Some overly paranoid MTA admins will have UCE measures in place that reject email relayed through different systems that are not retraceable from certian headers - as in the case of relaying through another smtp server. But then again, a lot of these people also reject on reverse lookups which tons of home users have no control/say over delegated arpa records. (double edge sword depending on your configurations)

postfix you would add something such as
relayhost = [gateway]
instead of trying to deliver directly (which is default) If they have SMTP-Auth setup instead of permitting open relay from their networks, you can do that too.

Of the ISP's that do this port filtering, a lot of them onlyt do it to monitor for TOS violations.



Anyways, just another option for people.

[Zodex]

Where would you set Sendmail up to point it towards the ISP mail gate ?