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Strange problem.

I have 2 computers connected to Wifi router.

One with Windows Vista & second with 2 operating systems: SUSe Linux and Windows 7 64bit on it.

Computer with Vista can connect to SMTP server of my email provider (and any other) using port 25, and can connect to a mail server using telnet mail.server.com 25 if this port is open.

Computer with dual operating system can (using Linux) do the same.

The same computer, with the same hardware (Wifi card etc.), and using the same WiFi router, cannot however use Port 25 and cannot Telnet into any smtp server.

So the problem is in Windows 7.

I did uninstall all antivirus software and disabled the firewall. The problem is still here.

Is there way how find out which software is blocking this port?

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migrated from serverfault.com Apr 2 '12 at 21:44

This question came from our site for professional system and network administrators.

2  
what result/error do you get? –  Mathias R. Jessen Apr 2 '12 at 21:39
    
Does this happen in Safe Mode with Networking too? –  Tom Wijsman Apr 2 '12 at 21:53
    
I did actually solve this problem by myself - it was virus blocking port 25, which haven't been detected by MS Security Essentials, but Avast Free Antivirus did the job. –  Michal Gow Apr 2 '12 at 22:21
    
Would you consider adding that as an answer and accepting it? If someone else has the same problem, they're more likely to look at this if it's listed as having an accepted answer. –  Darael Apr 3 '12 at 10:04

1 Answer 1

up vote -2 down vote accepted

I did actually solve this problem by myself - it was virus blocking port 25, which haven't been detected by MS Security Essentials, but Avast Free Antivirus did the job.

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I would get rid of Avast I have had many client's bring their computers in because of that program. –  Ramhound Apr 3 '12 at 10:57
    
I actually did try NOD32 first, but installation - maybe because the virus - crashed several times –  Michal Gow Apr 3 '12 at 14:04

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