My SMTP port 25 is Blocked by my ISP
InterServer Web Hosting servers have opened port 25000 and 2500 for our customers who require SMTP services but their ISP blocks port 25.
This change will not affect current users that are able to use port 25. It allows the users who can not user it to have another port to connect to for the purposes of sending E-Mail.
ISP that block Port 25:
- AT&T (can be unblocked at the request)
- People PC
- Comcast ATTBI
To manually test your mail server you can perform the following
- Open a command prompt (start>run>cmd in windows 2000 or greater)
- Type “telnet [your mail server IP] 25” don’t forget the port number – – – this will open an SMTP connection
- Type “helo yourdomain.com” – – – server will respond “220 mx.mydom.com SMTP”
- Type “mail from:<email@example.com>” – – – server responds “250 Address Ok”
- Type “rcpt to:<firstname.lastname@example.org>” – – – server responds “550 not local host someotherdomain.com, not a gateway”
- Type “data”
- Type “subject:Some email subject”
- Type “Text for the email body”