Outgoing mail when sent over comcast not working

My outgoing email has suddenly stopped working when I am running from my Comcast ISP. When I use some other network such as a verizon MIFI, mail works fine.

What would prevent email from going out when on my Comcast network?

Thanks in advance!

If your using comcast SMTP you might want to ask here instead. If I’ve misunderstood you might want to explain more.

On the surface, it sounds like a comcast issue. Works when not on comcast, but does not work when on comcast.

However, I read some posts from a year or so back where somehow Dreamhost started blocking ip addresses from comcast due to what appeared to be spam being sent from comcast ip addresses.

I am not really sure how to troubleshoot this to determine where it is getting blocked.

Is there anything I can look at? Or have dreamhost or comcast look at?

Unless my account has been hijacked, I do not send email except for manually created email do I do not believe that I would have been interpreted as a spammer.

Any suggestions???

what are you using to send mail?

FWIW, comcast sometimes blocks dreamhost mail, that is from:dreamhost account to:comcast account. I haven’t actually had a problem with that recently tho (yes I have a comcast account)

now if you are trying to send “from” a dreamhost account with a local client like outlook or thunderbird and you are trying to use a comcast smpt server, you wouldn’t be able to do that if your comcast account is residential. Residential user can only send from their @comcast.net address using comcasts outbound mail sever (SMTP). If you have comcast business class, it is possible to configure to send mail from your dreamhost domain via a comcast outbound server but it requires advanced configuration on the comcast side and additional DNS records on the dreamhost side.

I consulted with one of our email experts here on our support team, and ze had this to say:

First guess, ComCast blocks port 25; We provide an alternate port 587 you can use instead. Port details in this wiki page:

Second guess, some ISPs require all outgoing mail use the ISP’s SMTP server for outgoing mail, regardless of the incoming mail server. You’d have to check with the ISP for that.

But because your problem is limited to just one internet connection, and you can send fine when using other internet connections, sounds like the issue is probably not with us.

If you’d like us to take a look though, please submit a ticket here with details of a specific email that didn’t send (sender & recipient email addresses and the date&time you tried), and we can see if we can figure something out for you!

I changed to a secure port and all is well. Thanks for pointing me to the article.


Of course that has nothing to do with dreamhost configuration at all.