Most internet service provider (ISP) blocks the particular port for their users and we can’t access that port like 25. ISP’s do this for the security reasons and that’s why you are not able to send mail from an email client. To resolve this problem mostly we use port 26 and run exim on this port to send emails from email client. But to ensure that your service provider blocks that particular port 25 you have to run command. Let’s see how we can do this.
How to check your ISP blocks port 25?
As we know many ISPs blocks port 25 but how we can check it at our end. You can check the block is block or not, if it’s blocked then you have to use alternate port 26 for SMTP traffic. To check that port 25 is block or not you have to run telnet command in command prompt like this :
If your command is successfully run in command prompt then it means your computer is able to connect to port 25 on SMTP server. Btu if not then you has to set alternative port 26 for SMTP server. You can easily change the alternative port to 26, which is the most common alternative port. If you have the same problem for SMTP port 25 blocks then you can change his settings by using WHM (web host manager).Code:Telnet domainname.com
How to configure server to run on alternative port?
If you need to set the alternative port on server then first you have to configure the port 26 on server by following the steps :
From all these steps you will be able to use another port 26 as an SMTP port.
- First login to WHM through this link : https://serverip:2087.
- Now find service manager in search box and search for it.
- Click on “service manager”.
- You have to check the box “exim on another port”.
- And set for port number 26.
- Click on save.