Jan 22, 2019 · SMTP Port 25: Port 25 is the oldest of the four. It was the port number assigned to SMTP when the protocol was first introduced in the now obsolete RFC 821 back in 1982, about 37 years ago. This SMTP port remains to be used primarily for SMTP relaying. SMTP relaying is the transmittal of email from the email server to the email server.

Can't access port 25 on my azure VM from my server - Stack So far so good, the problem is that I can't connect to this VM from my physical windows server, I opened it port 25 (outbound) but yet when I check with PortQRY.exe (microsoft tool) I get TCP port 25 (smtp service): FILTERED A Quick Port Scanning Tutorial | Nmap Network Scanning Nmap scan report for scanme.nmap.org ( Not shown: 65530 filtered ports PORT STATE SERVICE VERSION 22/tcp open ssh OpenSSH 4.3 (protocol 2.0) 25/tcp closed smtp 53/tcp open domain ISC BIND 9.3.4 70/tcp closed gopher 80/tcp open http Apache httpd 2.2.2 ((Fedora)) |_HTML title: Go ahead and ScanMe! 113/tcp closed auth Device type Global Information Assurance Certification Paper

When email is delivered, servers talk to each other using the Transmission Control Protocol (TCP) over port 25. Just as the Hypertext Transfer Protocol (HTTP) that powers the web uses port 80, SMTP uses port 25. For more than a decade, many Internet Service Providers (ISPs) have blocked or severely restricted the use of port 25 because home

Jan 22, 2019 Solved: Verizon is blocking TCP port 25 - Verizon Fios

Port(s) Protocol Service Details Source; 26 : tcp: rsftp: Port used by RSFTP - a simple FTP-like protocol. Sometimes also used as an alternate to port 25 SMTP (Simple Mail Transfer Protocol).

iptables: open port 25 CentOS 7 - Server Fault