Port reference
Look up a port, then copy a command to test it.
How to use it
- Type a port number or a name, such as 443 or RDP.
- Read what uses that port and whether it's TCP or UDP.
- Fill in a host and copy the test command to check it's open from your PC.
Common ports
- 20/21 TCP: FTP (data/control). Plain text. Prefer SFTP on 22.
- 22 TCP: SSH / SFTP / SCP
- 23 TCP: Telnet. Unencrypted. Still used on old switches and for quick port tests.
- 25 TCP: SMTP relay. Server-to-server mail. Most ISPs block it outbound.
- 53 TCP/UDP: DNS
- 67/68 UDP: DHCP (server/client)
- 69 UDP: TFTP. PXE boot and switch config backups.
- 80 TCP: HTTP
- 88 TCP/UDP: Kerberos
- 110 TCP: POP3
- 123 UDP: NTP. Time drift over 5 minutes breaks Kerberos sign-in.
- 135 TCP: RPC endpoint mapper
- 137-139 TCP/UDP: NetBIOS
- 143 TCP: IMAP
- 161/162 UDP: SNMP (polling/traps)
- 389 TCP/UDP: LDAP
- 443 TCP: HTTPS
- 445 TCP: SMB file shares
- 465 TCP: SMTPS (implicit TLS)
- 500/4500 UDP: IPsec IKE / NAT-T
- 514 UDP: Syslog
- 587 TCP: SMTP submission. What mail clients and scanners should use to send.
- 636 TCP: LDAPS
- 853 TCP: DNS over TLS
- 993 TCP: IMAPS
- 995 TCP: POP3S
- 1194 UDP: OpenVPN
- 1433 TCP: Microsoft SQL Server
- 1521 TCP: Oracle database
- 1812/1813 UDP: RADIUS (auth/accounting)
- 3268/3269 TCP: AD Global Catalog (/SSL)
- 3306 TCP: MySQL / MariaDB
- 3389 TCP/UDP: Remote Desktop
- 5060/5061 TCP/UDP: SIP (/TLS)
- 5432 TCP: PostgreSQL
- 5900 TCP: VNC
- 5985/5986 TCP: WinRM (HTTP/HTTPS). PowerShell remoting.
- 8080 TCP: HTTP alternate / proxies
- 8443 TCP: HTTPS alternate / admin consoles
- 9100 TCP: Raw printing (JetDirect)
- 631 TCP: IPP printing
- 51820 UDP: WireGuard