Linux Ports#
Reference of well-known port assignments on Linux systems. The operator consults this during scan triage and target development.
Selected ports#
Port |
Proto |
Service |
Description |
|---|---|---|---|
21 |
TCP |
ftp |
File Transfer Protocol |
22 |
TCP |
ssh |
Secure Shell |
23 |
TCP |
telnet |
Telnet |
25 |
TCP |
smtp |
Simple Mail Transfer Protocol |
53 |
TCP / UDP |
domain |
DNS (BIND) |
67 |
UDP |
bootps |
DHCP server |
68 |
UDP |
bootpc |
DHCP client |
69 |
UDP |
tftp |
Trivial FTP |
80 |
TCP |
http |
HyperText Transfer Protocol |
88 |
TCP |
kerberos |
Kerberos |
110 |
TCP |
POP3 |
Post Office Protocol v3 |
111 |
TCP |
sunrpc |
Remote Procedure Call (NFS) |
123 |
UDP |
ntp |
Network Time Protocol |
137-139 |
TCP / UDP |
netbios |
NetBIOS Name / Datagram / Session |
143 |
TCP |
IMAP |
Internet Message Access Protocol |
161 |
UDP |
snmp |
Simple Network Management Protocol |
162 |
UDP |
snmptrap |
SNMP traps |
389 |
TCP |
ldap |
Lightweight Directory Access Protocol |
443 |
TCP |
https |
HTTP over TLS |
445 |
TCP |
microsoft-ds |
SMB over TCP/IP |
464 |
TCP |
kpasswd |
Kerberos password change |
465 |
TCP |
smtps |
SMTP over TLS |
500 |
UDP |
isakmp |
IKE / ISAKMP |
512-514 |
TCP / UDP |
exec / login / shell / syslog |
r-services and syslog |
587 |
TCP |
submission |
Mail submission agent |
636 |
TCP |
ldaps |
LDAP over TLS |
993 |
TCP |
IMAPS |
IMAP over TLS |
995 |
TCP |
POP3S |
POP3 over TLS |
1080 |
TCP |
socks |
SOCKS proxy |
1433-1434 |
TCP |
ms-sql |
Microsoft SQL Server / Monitor |
1521 |
TCP |
oracle |
Oracle (informally) |
1701 |
UDP |
l2tp |
Layer 2 Tunneling Protocol |
1812-1813 |
UDP |
radius |
Radius auth / accounting |
2049 |
TCP / UDP |
nfs |
Network File System |
3128 |
TCP |
squid |
Squid web proxy |
3306 |
TCP |
mysql |
MySQL |
3389 |
TCP |
rdp |
Remote Desktop Protocol (informally) |
4444 |
TCP / UDP |
krb524 |
Kerberos v5 to v4 translator (also common attacker default) |
5432 |
TCP |
postgres |
PostgreSQL |
5900 |
TCP |
vnc |
VNC (informally) |
6000-6010 |
TCP |
x11 |
X Window System |
6667 |
TCP |
ircd |
Internet Relay Chat |
8008 |
TCP |
http-alt |
HTTP alternate |
8080 |
TCP |
webcache |
WWW caching service |
9100 |
TCP |
jetdirect |
HP JetDirect printing |
27374 |
TCP |
asp |
Address Search Protocol |
33434 |
UDP |
traceroute |
Traceroute |
Pages 134-143 of the source handbook give the full table; the entries above cover the ports the operator hits day to day.