问题
I'm using a windows 7 PC
When I try to test an smtp connection through telnet giving the command:
telnet smtp.gmail.com 25
It shows a message:
could not establish connection to host, on port 25: connection failed"
How do I get my PC to establish a connection with the smtp host on port 25?
I checked the possibility of a Firewall blocking the port and also try using the telnet command on ports 465 or 587.
回答1:
It works for me. Perhaps your ISP has a policy of blocking outbound port 25 connections, except to their official outgoing SMTP servers. That's why many services support alternate port numbers for their SMTP service. You didn't say what the results were for the alternate ports, so it's hard to say for sure whether that's your problem.
回答2:
I also faced the same problem. The solution works for me
Either off the firewall OR Follow the below steps:
- Open Windows Firewall with Advanced Security
- Open Inbound Rules New Rule
- Choose Port type
- Choose TCP, and enter the required port - in our case, 25
- Choose to Allow the connection Choose all three profiles (Domain+Private+Public)
- Enter a custom rule name, e.g. "Port 25"
- Press finish
Check whether SMTP port 25 is opened or not
a. Open up a command prompt.
b. Type “telnet <server_ip> 25” then hit enter.
c. Once you are determined the results. Type quit and hit enter
Important: Antivirus software can help protect your computer against viruses and other security threats. In most cases, you shouldn't disable your antivirus software. If you have to temporarily disable it to install other software, you should re-enable it as soon as you're done. If you're connected to the Internet or a network while your antivirus software is disabled, your computer is vulnerable to attacks.
- Click Start, Programs, McAfee, VirusScan Console.
- Double-click Access Protection
- select Anti-virus Standard Protection
- Unchecked enable access
来源：https://stackoverflow.com/questions/4832238/could-not-connect-smtp-server-on-port-25