How Pervasive is ISP Outbound Email Filtering?

Erris writes "A member of the Baton Rouge LUG noticed that Cox checks the text of outgoing email and rejects mail containing key phrases. I was aware of forced inbox filtering that has caused problems and been abused by other ISPs in China and in the US. I've also read about forced use of ISP SMTP and outbound throttling, but did not know they outbound filtered as well. How prevalent and justified is this practice? Wouldn't it be better to cut off people with infected computers than to censor the internet?"

Comments

Re:Not Comcast

[squallbsr]

I also have Comcast, I was able to send email over SMTP (port 25) any time I pleased. That was until my brother decided to bring over his virus ridden, spam spewing, zombified windows machine over and hook it up to my network (while he was house sitting). They promptly blocked port 25, I got home and couldn't send email.

I had to call their very rude Security Something Department, they said my options were
1. 'Use a different port because other ports can be secured while port 25 cannot be secured.'
2. Use the Comcast alternate port SMTP-AUTH Server (of which I don't know my login/password for)

I told them I wanted option 3:
3. Re-open port 25.

They decided to tell me that they could as a ONE TIME courtesy re-open the port, but 'it will probably be blocked again because the problem that caused it to be blocked probably wasn't fixed' (even after I told them that I had found the problem and fixed it, in addition to monitored all transmissions over port 25 for an hour)... So I fixed my OpenBSD firewall pf rules to only allow 'trusted' computers to only be able to contact MY email server, and access the whole internet unfettered, the 'guest' machines have access to web and a handful of other ports (none of which is 25)...

Moral of the story: Stop using windows... /flamebait