Tech Support > Computers & Technology > Internet & Broadband > Re: Port Blocking on BTBroadband ?
Re: Port Blocking on BTBroadband ?
Posted by Destinations Couriers on July 4th, 2003



Steve

The blocking of port 25 should not affect any other email services that you
use. I am on BTOW here at my office and port 25 is definitely closed to me
because I cannot use MailWasher to Delete or Bounce messages sitting on the
BTConnect servers. I can however use MailWasher ok with my other mail
accounts that are with other providers via our BTOW connection. I can also
send and receive ok form these other providers using the standard Outlook
settings.





Posted by Andy Jenkins on July 4th, 2003


On Fri, 4 Jul 2003 12:25:57 +0000 (UTC), "Destinations Couriers"
<j020@btclick.com> wrote:

Hi,

I think you have misunderstood how this Port 25 closure has been / is
being done.

Port 25 will be closed for the *local* machine only .. ie *your*
machine. At this moment, your PC is running with x number of ports,
some will be open, and some will be closed. If the machine at the end
of your IP address was an SMTP server, then, by RFC 821 (iirc) your
machine must be *listening* on Port 25. If you are not, or
communication from your ISP to you results in packets destined for
Port 25 being thrown out the window, then no-one would be able to get
their email to you.

In the vast majority of cases, people will not be running their own
email servers, choosing instead to connect to an SMTP somewhere on the
internet, or most likely on their ISPs network. To connect to someone
elses SMTP server (ie, that is not on BTOpenworld network), would
require that you talk via Port 25, the remote machine listens on Port
25. Communication _back_ to you, with the emails that you have
requested to be downloaded, will be any random port above 1024 (again,
iirc)

In short, your failure to use Mailwasher from your office connection
is not due to the Port 25 senario, but another issue. What I am not
sure though ...

--
Andy Jenkins
www.btofaq.net
&
www.btofaq.net/v3/forum

Posted by Uncle Wobbly on July 4th, 2003


mailwasher deletes using POP3... port 110. True, you won't be able to bounce
(with 25 blocked), but MW uses exactly the same method to delete as your
mail client does to get your mail.




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