There has been a lot of reports that Comcast is selective blocking outbound TCP port 25 and now seems to also block the inbound port as well. TCP Port 25 is used for SMTP, the email protocol for downloading email from a mail server to a third party email client.
More and more ISPs limit port 25 access in order to cut down on spam sent through their servers. But it also prevents legitimate users from sending email with third party mail hosting services, including even their own web sites’ domain names.
Comcast Tech Support doesn’t seem to be aware of any change and Comcast hasn’t informed their subscribers that port 25 is now blocked both ways but many Comcast users have begun complaining about their mail being blocked on message boards over the past few weeks. Some users are also claiming that Comcast Support has told them that they need to upgrade their service to a business account but I haven’t been able to get any Techs to suggest this to me.
Are you having problems? Did you contact Comcast? What did they tell you?
[tags]comcast, port 25, email, mail, e-mail, smtp, TCP port 25[/tags]