Forums

OT: How much traffic does your ISP filter by TCP port no.?

Started by Didi November 28, 2007
 A few days ago my ISP blocked my outgoing TCP connections to
port 25 - except to their mailserver. After a few calls they agreed to
let me also access my domains mailserver (turned out they just
allowed it globally to all their customers...).
 I sometimes use my domains mailserver or my ISP's, but at times,
e.g. when I want to have the delivery session to the final recipient
mailserver
logged, I let my SMTP client go all the way directly.
 They claim they did it to fight spam - which is plausible, but breaks
their claim to deliver "unlimited access" in pieces.
 And since no spam comes out of here, I do not like what they did.
 Not something I would go to war for, but I will not ignore this
lightly
either.
 Any observations from other parts of the world? (I am located in
Sofia, Bulgaria).

Thanks,

Dimiter

P.S. Hint: if you don't know whether your ISP blocks your outgoing
SMTP connections, try to connect to my domains mailserver,
telnet://mail.tgi-sci.com:25 . If you see a response (one line),
you are not blocked. Type in a "quit" command to close the session
gracefully.

------------------------------------------------------
Dimiter Popoff               Transgalactic Instruments

http://www.tgi-sci.com
------------------------------------------------------
http://www.flickr.com/photos/didi_tgi/sets/72157600228621276/
On a sunny day (Wed, 28 Nov 2007 19:07:33 -0800 (PST)) it happened Didi
<dp@tgi-sci.com> wrote in
<76b81269-0d5f-4efa-ae62-b178af846824@g30g2000hsb.googlegroups.com>:

> A few days ago my ISP blocked my outgoing TCP connections to >port 25 - except to their mailserver. After a few calls they agreed to >let me also access my domains mailserver (turned out they just >allowed it globally to all their customers...). > I sometimes use my domains mailserver or my ISP's, but at times, >e.g. when I want to have the delivery session to the final recipient >mailserver >logged, I let my SMTP client go all the way directly. > They claim they did it to fight spam - which is plausible, but breaks >their claim to deliver "unlimited access" in pieces. > And since no spam comes out of here, I do not like what they did. > Not something I would go to war for, but I will not ignore this >lightly >either. > Any observations from other parts of the world? (I am located in >Sofia, Bulgaria). > >Thanks, > >Dimiter
Well it is the same here in the Netherlands. I do not have an ISP, but a direct line to the telco, but even then they intercept port 25, use there own server, and resend to me on port 25. I send mail via their mail relay. I must say, that it saves me checking log files etc... Already plenty of work keeping the http and other servers clean. The disadvantage is, that sometimes their server is down, or offline for maintenance. The advantage is, that if my server is down, the incoming email does not bounce, but I get it as soon as my system is up again. That last advantage may be important. Although my server is up 24/7, and has a backup, still it may offline for several reasons, like a 5 hour long power failure last month because some workers digging cut a power cable. Maybe I should buy a Honda generator....