Tek-Tips is the largest IT community on the Internet today!

Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!

  • Congratulations Chriss Miller on being selected by the Tek-Tips community for having the most helpful posts in the forums last week. Way to Go!

ISP Blocked Port 1

Status
Not open for further replies.

shmoes

MIS
Apr 24, 2003
567
CA
Hey all,

ok after racking my brain going through post after post after post.. i've finally found the problem!!

basically i've setup an email accout in outlook, only to find that it refuses to send, i've verified all the settings accounts, firewalls, antivirus etc etc. and then i stumbled on a post that says;

1. The Outgoing (SMTP) server requires authentication.
If you are using Outlook Express you should check the box 'My server requires authentication'.

2. If you are behind a firewall, we may be unable to authenticate you.
If you have a personal firewall, try lowering the security or disabling it to see if it is causing the issue.
(Remember to re-enable it after testing)

3. Your SMTP (outgoing mail server) could be blocked.
Here is how to test it:
A. Go to Start -> Run -> type: cmd
B. When the Command prompt appears type: telnet smtp.gct21.net 25
(include the spaces exactly as shown above)

C. Wait a few seconds. You should see the following: '220 mail4.gct21.net ESMTP'. This means that it is not blocked.
D. If you do not see this message, your SMTP is being blocked.

so even though it's an unrelated isp that's giving this info i decided to try it. sure enough it's blocked on my telus server (verified i can connect from another network)

so the million dollar question is how do i get around the blocked port? :\


~Shmoes

 
In Outlook (Office) I don't have to check any box that says anything about Authentication or Security and just leave it blank. I do have an ISP Password to use to get to my E-mails but not to Authenticate on their Server.

Have you tried it without checking the box just to see if you can get through?
 
The authentication tickbox is on the "outgoing server" tab of your mail account properties.

If ticking it does not fix your problem, you may have to contact your ISP requesting they allow you to smtp through their server
 
Many ISPs who block port 25, such as optonline.net, do it only for domesctic customers, but if you have a business class account you can get them to open it.

Otherwise there's nothing you can do but use a different provider.

If you have a gmail account, you can send smtp via smtp.gmail.com on port 495 (requires authentication and ssl). Possibly your ISP doesn't block that one.

Jock

 
Vista HP & Outlook 2K7 - Can't send - resolved but why?
thread1583-1391593

Can someone please help me to figure out this problem with OE 6 in XP
thread779-1093219
 
ok, the "why" is still not answered and I'm worried that it'll end up biting me in the ass, but changing to port 587 as per linney's last post link, and that did work .. but for how long? :|



~Shmoes

 
Let us know what your ISP have to say on the matter, if you decide to contact them.
 
I imagine that your ISP is blocking outbound port 25 connections to anything other than their own mail servers as a method to cut down on spam sent by their users. If some of your ISP's clients were [unknowingly] part of a botnet that sends outbound spam on the standard port 25, they would be blocked. This is fairly common for ISP and many businesses.
 
I agree with the above. Port 25 is blocked on a great many ISP, in an effort to curb basic SMTP generated spam. It's a pain, but if people bother to get AV software (and keep it up to date) and a even basic firewall, they would have no need to.
Blame the idiots out there, not the ISP's for this one.

Only the truly stupid believe they know everything.
Stu.. 2004
 
Status
Not open for further replies.

Part and Inventory Search

Sponsor

Back
Top