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Every time I try to open a hostname , the following

Microsoft Telnet> o example.domain 25
Connecting to example.domain... Could not open connection to the host, on port 25: Connect failed

error message occurs. Why and how to fix it? I work on the Windows 7 professional x64 with turned off firewall.

Where the port number was checked

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Many ISPs block port 25, you should call your ISP and check if they do. If they do, you should see if your mail provider has an alternate port you can use, many will as this is a common issue. – MaQleod Jun 18 '12 at 18:05
@MaQleod In my case, you're right. – 0x6B6F77616C74 Jun 18 '12 at 18:31
up vote 0 down vote accepted

The only culprit was my ISP that has blocked the port 25.

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