Important Port Numbers for Linux Admins
- A port number is part of the addressing information used to identify the senders and receivers of messages. Port numbers are most commonly used with TCP/IP connections.
- Port numbers range is 0 to 65535, means total port numbers are 65536, The port number field is 16-bit size.So we get only 2^16(2 to the power of 16) ports , its equal to 65536 ports
- Default ports are 0 to 1023 (2^10=1024 ports), default ports means particular well known services such as ftp server, web server, mail server, dns server, samba server nfs server etc.., these servers are using default port numbers(dns=53, ftp=21, Apache=80, samba=139)
# vim /etc/services
Important Port Numbers :
PORT
|
NAME
|
COMMENT
|
1
|
tcpmux
|
TCP Port Service multiplexer
|
7
|
echo
|
Echo service
|
20
|
FTP Data
|
File Transfer Protocol - For transferring FTP data
|
21
|
FTP Control
|
For starting FTP connection
|
22
|
SSH
|
Secure Shell
|
23
|
Telnet
|
For insecure remote administration
|
25
|
SMTP
|
Send Mail Transfer Protocol
|
43
|
WHOIS service
| |
53
|
DNS
|
Domain Name System
|
67
|
Bootp
|
Bootstrap Protocol(DHCP-client to server communication)
|
68
|
DHCP
|
Dynamic Host Configuration Protocol(Server to client communication)
|
69
|
TFTP
|
Trivial file transfer protocol uses udp protocol for connection less transmission of data
|
80
|
HTTP/WWW
|
Hypertext Transfer Protocol/apache
|
88
|
Kerberos
|
Kerberos is a computer network authentication protocol which works on the basis of 'tickets' to allow nodes communicating
|
110
|
POP3
|
Post Office Protocol - Mail delivery Agent
|
111
|
Rpcbind
|
part of the portmap package
|
123
|
NTP
|
Network time protocol used for time syncing uses UDP protocol
|
137
|
NetBIOS(nmbd)
| |
139
|
SMB-Samba(smbd)
|
SAMBA Server
|
143
|
IMAP
|
Internet Message Access Protocol
|
161
|
SNMP
|
Simple Network Management Protocol - For network monitoring
|
389
|
LDAP
|
Lightweight Directory Access Protocol - For centralized administration
|
443
|
HTTPS
|
HTTP+SSL for secure web access
|
514
|
Syslogd
| |
636
|
ldaps
|
LDAP over SSL - both tcp and udp
|
873
|
Rsync
|
Remote sync
|
989
|
FTPS-data
| |
990
|
FTPS
|
Also known as FTP-ES, FTP-SSL and FTP Secure
|
993
|
IMAPS
|
IMAP Secure
|
995
|
POP3s
|
POP over SSL
|
1194
|
openVPN
|
virtual private network
|
1812
|
RADIUS
|
Remote Authentication Dial In User Service
|
2049
|
NFS
|
Network File System
|
2401
|
CVS server
|
Concurrent Versioning System
|
3128
|
Squid Proxy
| |
3306
|
MySql
|
Mysql Database
|
3690
|
SVN
|
Apache Subversion
|
8008
|
http-alt
|
Hypertext Tranfer Protocol (HTTP) alternate
|
8080
|
Webcache
|
World Wide Web(WWW) caching service
|
10000
|
Webmin
| |
6000 -6063
|
X11
|
X11 use 6000 to 6063.. ports for connecting X11 from remote server
|
