haw i can open port 2121

dr.dermann · 10-29-2006, 02:18 AM

hi all
i wont know haw can i open port 2121
i forget haw
can any one help me plz

tlowk · 10-29-2006, 03:13 AM

This question is a bit ambuigous but I assume you have a firewall and want to open it for that specific port (udp or tcp)

iptables -I INPUT -p tcp --dport 21212 -j ACCEPT
iptables -I INPUT -p udp --dport 21212 -j ACCEPT

you could test with a tool
nc -l -p 2121

and see what happens if your try a telnet from another machine

telnet YOURMACHINE 2121

I hope to make a right guess about what you nee

dr.dermann · 10-29-2006, 03:27 AM

bash-2.05b# ./nc
Cmd line: nc -l -p 2121
nc: forward host lookup failed: Host name lookup failure : Resource temporarily unavailable

tlowk · 10-29-2006, 03:32 AM

what is shown when you type hostname? I don't see much relation with nc anyway.

another way to see it

tcpdump -i any tcp port 2121
tcpdump -i any udp port 2121

as root will show all traffix on that port for all network interfaces

tlowk · 10-29-2006, 03:34 AM

what is shown when you type hostname? I don't see much relation with nc anyway.

another way to see it

tcpdump -i any tcp port 2121
tcpdump -i any udp port 2121

as root will show all traffix on that port for all network interfaces

dr.dermann · 11-02-2006, 09:27 AM

i see this massage

bash-2.05b# iptables -I INPUT -p tcp --dport 2121 -j ACCEPT
bash-2.05b# iptables -I INPUT -p udp --dport 2121 -j ACCEPT
bash-2.05b# cd /usr/bin
bash-2.05b# ./nc
Cmd line: nc -l -p 2121
nc: forward host lookup failed: Host name lookup failure : Resource temporarily unavailable
bash-2.05b#

raska · 11-02-2006, 09:53 AM

Quote:

Originally Posted by dr.dermann

...nc: forward host lookup failed: Host name lookup failure : Resource temporarily unavailable...

mmmmh, check this:
Do you have your machine's hostname listed in /etc/hosts with a proper IP address? That IP address can be localhost, 127.0.0.1

Also after the iptables commands, check with iptables -L -n to see if it is respecting your firewall rules.

Another way to open a port is to list it in the /etc/inetd.conf file though you have to assign it a service and restart the inetd server, after that of course you should configure your firewall accordingly if any, or nothing would reach the port.

dr.dermann · 11-06-2006, 07:34 PM

iptables -L -n
ACCEPT udp -- 0.0.0.0/0 0.0.0.0/0 udp dpt:2121
ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 tcp dpt:2121

Chain FORWARD (policy ACCEPT)
target prot opt source destination

Chain OUTPUT (policy ACCEPT)
target prot opt source destination