By default it listens on SMTP port 25
Port 25
pretty much anything that can run Linux and sendmail
1. "hello" change and you have to edit the mail server file.
1. "hello" change and you have to edit the mail server file.
By "change port in Linux", I assume you mean changing the default port an application listens or transmits on. This is usually set in the program's settings or configuration file.
Port scannerAnswer Explanation: To help assess vulnerabilities relating to a network's security, use a port scanner. Port scanners are used to look for open ports on a network host. Port scanners can detect computer network services that a remotely located system is providing.
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Port 23
32239
Cups uses port 631 by default
Edit the ports.conf file and change the line listen 80 to listen 81 which is, all in all, remarkably straightforward.
SMTP is normally run on port 25, regardless of what operating system is running the service.
The FTP port has been standardized at port 21, so it is highly unlikely it is operating on another port. To change the port, you would have had to change configuration settings. And if you had, you would know what port it was on.