Comcast blocking outgoing port 25

Comcast announced today they’re blocking outbound port 25 for their residential customers. What does this mean for email marketers? Not much, unless your home connectivity is through Comcast and then you’ll just need to follow Comcast’s directions in order to send mail. What does it mean for email receivers? It means a lot of us will be seeing a lot less spam from infected Windows machines.


  1. William says

    Hmm, I see no mention of the fact that (as of my last discussion with them) they do not allow use of their own SMTP servers for outbound unless you are using an address. Cue the Verizon 2001 replay.

  2. Andrew from Vancouver says

    I thought they did this forever-ago. Once upon a time, spam directly from a ComCast consumer IP was common. It’s been years since I noticed spam coming directly from a ComCast IP. For that matter, it’s also rare to see freemail spam that originated on a Comcast zombie IP. Kudos to them!


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