Comcast and Port 25 Blocking

[Jerry Feldman]

On Thursday 28 July 2005 12:50 pm, Matthew Gillen wrote:
> bill at horne.net wrote:
> > Conclusion: I think Comcast has some automated system that blocks port
> > 25 based on criteria they don't want to reveal. The guy I talked to
> > said any blocking happens at the cable modem, so I don't know if
> > changing the MAC address so as to get a different IP would make any
> > difference.
>
> I know (from looking at my mail server's logs) they run relay tests once
> a month or so to see if your server is an open relay.  I don't know if
> they do anything more sophisticated.
This is something you should do yourself occasionally. There are a number of 
sites that do open relay checks. it is very possible that when discovering 
an open-relay that Comcast automatically sets a block on port 25.

-- 
Jerry Feldman <gaf at blu.org>
Boston Linux and Unix user group
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