查看linux服務器所開放的端口

查看和了解linux服務器所開放和使用的端口是維護工做中比較重要的工做。（以redhat server 5 爲例）

一、nmap命令

# nmap -sT -O localhost

Starting Nmap 4.11 ( http://www.insecure.org/nmap/ ) at 2010-01-22 08:50 CST
Interesting ports on syapp1 (127.0.0.1):
Not shown: 1667 closed ports
PORT     STATE SERVICE
21/tcp   open  ftp
25/tcp   open  smtp
80/tcp   open  http
111/tcp  open  rpcbind
513/tcp  open  login
514/tcp  open  shell
631/tcp  open  ipp
2049/tcp open  nfs
3306/tcp open  mysql
5001/tcp open  commplex-link
5003/tcp open  filemaker
8009/tcp open  ajp13
8080/tcp open  http-proxy
No exact OS matches for host (If you know what OS is running on it, see http://www.insecure.org/cgi-bin/nmap-submit.cgi).
TCP/IP fingerprint:
SInfo(V=4.11%P=x86_64-redhat-linux-gnu%D=1/22%Tm=4B58F65C%O=21%C=1)
TSeq(Class=RI%gcd=1%SI=41495C%IPID=Z%TS=1000HZ)
TSeq(Class=RI%gcd=1%SI=414957%IPID=Z%TS=1000HZ)
T1(Resp=Y%DF=Y%W=8000%ACK=S++%Flags=AS%Ops=MNNTNW)
T2(Resp=N)
T3(Resp=Y%DF=Y%W=8000%ACK=S++%Flags=AS%Ops=MNNTNW)
T4(Resp=Y%DF=Y%W=0%ACK=O%Flags=R%Ops=)
T5(Resp=Y%DF=Y%W=0%ACK=S++%Flags=AR%Ops=)
T6(Resp=Y%DF=Y%W=0%ACK=O%Flags=R%Ops=)
T7(Resp=Y%DF=Y%W=0%ACK=S++%Flags=AR%Ops=)
PU(Resp=Y%DF=N%TOS=C0%IPLEN=164%RIPTL=148%RID=E%RIPCK=E%UCK=E%ULEN=134%DAT=E)

Uptime 0.610 days (since Thu Jan 21 18:12:54 2010)

Nmap finished: 1 IP address (1 host up) scanned in 9.955 seconds

二、lsof命令

/usr/sbin/lsof -i :端口

# /usr/sbin/lsof -i :3422

COMMAND  PID USER   FD   TYPE DEVICE SIZE NODE NAME sshd    3828 root    3u  IPv6  10063       TCP *:ssh (LISTEN)