Thanks, but currently I have an embedded linux board (based on openwrt) that use busybox, and there isn't netstat, neither nmap or lsof command. I guess i can read /proc/net/tcp or udp, but iptables doesn't show a list of used ports? On Fri, Nov 6, 2009 at 1:49 PM, Lisa Kachold wrote: > > > On Fri, Nov 6, 2009 at 5:30 AM, Craig White wrote: > >> On Fri, 2009-11-06 at 13:13 +0000, Marco Savo wrote: >> > Hello, >> > configuring iptables rules, >> > how I can find out if one port number I want to use is already in >> > use? >> > example: >> > >> > $IPTABLES -t nat -I zone_wan_prerouting 1 -j ACCEPT --protocol udp >> > --dport ${UDP_PORT} --destination localhost >> > $IPTABLES -t nat -I zone_wan_prerouting 1 -j ACCEPT --protocol tcp >> > --dport ${TCP_PORT} --destination localhost >> > $IPTABLES -t nat -I zone_wan_prerouting 1 -j ACCEPT --protocol tcp >> > --dport ${TCP_HOST_PORT} --destination localhost >> > >> > How I can check if these ports (UDP_PORT TCP_PORT TCP_HOST_PORT) are >> > in use from another application? >> ---- >> you can use netstat - for example, I might check for port 10000... >> # netstat -an|grep 10000 >> tcp 0 0 0.0.0.0:10000 0.0.0.0:* LISTEN >> udp 0 0 0.0.0.0:10000 0.0.0.0:* >> >> Craig >> >> >> You can also use nmap > > # nmap localhost > > or > > # netstat -anpt > > to see what is listening on what (depending on your distro - check syntax > > > -- > Skype: (623)239-3392 > AT&T: (503)754-4452 > www.obnosis.com > > > > > > > > > > > > > --------------------------------------------------- > PLUG-discuss mailing list - PLUG-discuss@lists.plug.phoenix.az.us > To subscribe, unsubscribe, or to change your mail settings: > http://lists.PLUG.phoenix.az.us/mailman/listinfo/plug-discuss > -- 'The Magic Is In the Movement' Marco Savo SW Engineer 882 East Glenn St. Tucson, AZ 85719 +1 (520) 248-5681