Port 25 (tcp/udp) - Online TCP/UDP Portfinder - adminsub.net

List of TCP and UDP port numbers - Wikipedia 248 rows Port 25 (tcp/udp) :: SpeedGuide 64 rows A Complete Guide to SMTP Port 25 | Pepipost Nov 29, 2019 TCP 25 - Port Protocol Information and Warning!

May 15, 2020 · Port 25. Port 25 is the oldest port. Request for Comments (RFC) 821 was published in 1982 when the University of Southern California submitted a proposal to the Internet Engineering Task Force (IETF), which established port 25 as the default transmission channel for internet email. From 1982 till date, Port 25 is used as the default port to

I have problems opening port 25 for sendmail on my CentOS 7 machine. Here's my iptables configuration: *filter :INPUT ACCEPT [0:0] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [0:0] -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT -A INPUT -p icmp -j ACCEPT -A INPUT -i lo -j ACCEPT -A INPUT -p tcp -m state --state NEW -m tcp --dport 22 -j ACCEPT -A INPUT -p tcp -m tcp --dport 25 -j ACCEPT -A

Aug 31, 2008

In that case you can change the default port - if you need it - to an alternative. The other option you have, is to use Nmap ↴ You can use nmap -sT localhost to determine which ports are listening for TCP connections from the network. To check for UDP ports, you should use -sU option. To check for port 25, you can easily use nmap -p25 localhost. This tool may also be used as a port scanner to scan your network for ports that are commonly forwarded. It is important to note that some ports, such as port 25, are often blocked at the ISP level in an attempt to prevent malicious activity. For more a comprehensive list of TCP and UDP ports, check out this Wikipedia article.