OT: ?? Comcast blocked my port 25

[Bill Campbell]

On Mon, Jan 26, 2009, Rick Bowers wrote:
> Hi all,
>
> On Wednesday (21 January) I received a message from Comcast saying they 
> have blocked port 25 on my modem (I didn't know you could configure a 
> SPECIFIC modem for that). They pointed me to directions for making things 
> work using port 587. It seems to work for one account, but not the others 
> -- even though I set them all up the same.
>
> I have run a mail server here at the house for more than 5 years. Until 
> now, all has been well. In addition to no longer being able to send 
> mails, all my incoming messages seem to be blocked. I haven't received 
> any new messages since 20 January. If I send from my GMail account, the 
> message eventually gets returned with a "connection timed out" error 
> code.
>
> Do any of you have any words of wisdom? I plan to call Comcast, but  
> would like to understand why blocking port 25 also affected my inbound 
> messages and why only one account works.  I'm guessing that a single 
> account ID/password is being used. I use Eudora as my mail client.

As others have said, many (most) broadband providers block
incoming and outgoing port 25 traffic on residential accounts to
prevent abuse (and complaints from large ISPs like AOL).  Many
ISPs also block incoming traffic from comcast residential IPs as
well so getting off port 25 is generally a Good Idea(tm).

Given that Comcast's residential contract specifies that one
cannot run servers, I wouldn't try complaining to them, but let
sleeping dogs lie.

We generally set our customers who are on comcast or other
broadband providers to send/receive e-mail through our systems on
a different port that I have never found blocked.  This is pretty
simple.  First it requires setting the MX record(s) for the
incoming domain(s) to point to one of our servers, and our
postfix servers to forward to the appropriate IP using the
transport table.  Outgoing mail from the customer's site is
likewise routed using their MTA's smart-host capabilities through
our servers.

We even have a few customers who send/receive through one of our
servers using uucp over tcp.

Bill
-- 
INTERNET:   bill at celestial.com  Bill Campbell; Celestial Software LLC
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