Some Internet Service Providers (ISPs) may block port 25 for sending mail. If you have an AIT web hosting account, and you use your server with AIT to send out email, and are not able to do so, it is quite possible that your ISP has implemented a policy where they block all email being sent out of their network using another server’s SMTP. They may require you to use their SMTP server.
More information on Verizon’s practice is here.
To test if you are being blocked, perform the following test.
- Open up a command prompt. You can do this by going to ‘Start’ then ‘Run’ and typing ‘cmd’ or ‘command.com’ on a Windows workstation. Use an xterm if you are using a MAC.
- At the prompt, type the following: telnet domainname.com 25
- If the port is open you will get an output that looks similar to: 220 domainname.com ESMTP Sendmail 8.13.8/8.13.1 Wed, Jun 2010 14:37:45
- If it is not open you will get an error.
Now, lets assume that the port is being blocked by your local ISP. In this case you have a few options.
Resolution Options
- Contact your ISP. Ask them what SMTP mail server you should use for your email program. This will be what you will fill into your “outgoing mail server” option in your email program.
- You can use the webmail that AIT provides.
- You can request that AIT change your SMTP port from port 25 to port 465 or port 587. More details on the email client configuration of this process is located here. Please note that you must request this change via AIT’s Customer Service / Trouble Ticket System first.