1、用netstat查看：
[grid@rac121 admin]$ netstat -anp | grep oracle
(Not all processes could be identified, non-owned process info
will not be shown, you would have to be root to see it all.)
udp 169.254.50.253: 0.0.0.0:* /oracle+ASM1
udp 127.0.0.1: 0.0.0.0:* /oracle+ASM1
udp 169.254.50.253: 0.0.0.0:* /oracle+ASM1_as
udp 169.254.50.253: 0.0.0.0:* /oracle+ASM1
udp 169.254.50.253: 0.0.0.0:* /oracle+ASM1
udp 127.0.0.1: 0.0.0.0:* /oracle+ASM1_as
udp 127.0.0.1: 0.0.0.0:* /oracle+ASM1
udp 169.254.50.253: 0.0.0.0:* /oracle+ASM1
udp 169.254.50.253: 0.0.0.0:* /oracle+ASM1
udp 169.254.50.253: 0.0.0.0:* /oracle+ASM1
udp 169.254.50.253: 0.0.0.0:* /oracle+ASM1_oc
udp 127.0.0.1: 0.0.0.0:* /oracle+ASM1
udp 169.254.50.253: 0.0.0.0:* /oracle+ASM1
udp 169.254.50.253: 0.0.0.0:* /oracle+ASM1_oc
udp 127.0.0.1: 0.0.0.0:* /oracle+ASM1
udp 169.254.50.253: 0.0.0.0:* /oracle+ASM1
udp 169.254.50.253: 0.0.0.0:* /oracle+ASM1_as
udp 127.0.0.1: 0.0.0.0:* /oracle+ASM1_oc
..............
unix [ ] STREAM CONNECTED - /var/tmp/.oracle/sOHASD_IPC_SOCKET_11
unix [ ] STREAM CONNECTED - /var/tmp/.oracle/sOHASD_IPC_SOCKET_11
[grid@rac121 admin]$ netstat -anp | grep
(Not all processes could be identified, non-owned process info
will not be shown, you would have to be root to see it all.)
tcp 10.1.252.68: 0.0.0.0:* LISTEN /tnslsnr
tcp 10.1.252.75: 0.0.0.0:* LISTEN /tnslsnr
tcp 10.1.252.121: 0.0.0.0:* LISTEN /tnslsnr
tcp 10.1.252.68: 10.1.252.68: ESTABLISHED -
tcp 10.1.252.68: 10.1.252.122: ESTABLISHED /tnslsnr
tcp 10.1.252.68: 10.1.252.68: ESTABLISHED /tnslsnr
tcp 10.1.252.75: 10.1.252.75: ESTABLISHED -
tcp 10.1.252.75: 10.1.252.75: ESTABLISHED /asm_pmon_+ASM1
tcp 10.1.252.75: 10.1.252.75: ESTABLISHED /tnslsnr
tcp 10.1.252.75: 10.1.252.75: ESTABLISHED /tnslsnr
tcp 10.1.252.75: 10.1.21.25: ESTABLISHED -
[grid@rac121 admin]$
2、lsof -i :port，使用lsof -i :port就能看见所指定端口运行的程序，同时还有当前连接。
[grid@rac121 admin]$ lsof -i :
COMMAND PID USER FD TYPE DEVICE SIZE NODE NAME
oracle grid 28u IPv4 TCP rac121-vip:->rac121-vip:ncube-lm (ESTABLISHED)
tnslsnr grid 14u IPv4 TCP rac121:ncube-lm (LISTEN)
tnslsnr grid 15u IPv4 TCP rac121-vip:ncube-lm (LISTEN)
tnslsnr grid 16u IPv4 TCP rac121-vip:ncube-lm->rac121-vip: (ESTABLISHED)
tnslsnr grid 18u IPv4 TCP rac121-vip:ncube-lm->rac121-vip: (ESTABLISHED)
tnslsnr grid 14u IPv4 TCP rac-scan:ncube-lm (LISTEN)
tnslsnr grid 15u IPv4 TCP rac-scan:ncube-lm->rac122: (ESTABLISHED)
tnslsnr grid 16u IPv4 TCP rac-scan:ncube-lm->rac-scan: (ESTABLISHED)
[grid@rac121 admin]$
3、nmap 端口扫描
[grid@rac121 admin]$ nmap 10.1.252.121 Starting Nmap 4.11 ( http://www.insecure.org/nmap/ ) at 2012-06-29 16:41 CST
Interesting ports on rac121 (10.1.252.121):
Not shown: closed ports
PORT STATE SERVICE
/tcp open ftp
/tcp open ssh
/tcp open domain
/tcp open rpcbind
/tcp open unknown
/tcp open oracle
/tcp open rna-lm
/tcp open cichild-lm
/tcp open sun-answerbook Nmap finished: IP address ( host up) scanned in 0.142 seconds
[grid@rac121 admin]$
4、文件/etc/services显示的各个服务的端口号:
[grid@rac121 admin]$ cat /etc/services | grep
ncube-lm /tcp # nCube License Manager
ncube-lm /udp # nCube License Manager
[grid@rac121 admin]$ cat /etc/services | grep oracle
oracle-oms /tcp # Oracle OMS
oracle-oms /udp # Oracle OMS
tlisrv /tcp # oracle
tlisrv /udp # oracle
oraclenames /tcp # oraclenames
oraclenames /udp # oraclenames
oraclenet8cman /tcp # Oracle Net8 Cman
oraclenet8cman /udp # Oracle Net8 Cman
oracle-em1 /tcp # oracle-em1
oracle-em1 /udp # oracle-em1
oracle-em2 /tcp # oracle-em2
oracle-em2 /udp # oracle-em2
oracle-vp2 /tcp # Oracle-VP2
oracle-vp2 /udp # Oracle-VP2
oracle-vp1 /tcp # Oracle-VP1
oracle-vp1 /udp # Oracle-VP1
oracle /udp
[grid@rac121 admin]$