Download your favorite Linux distribution at LQ ISO.
Go Back > Forums > Linux Forums > Linux - Networking
User Name
Linux - Networking This forum is for any issue related to networks or networking.
Routing, network cards, OSI, etc. Anything is fair game.


  Search this Thread
Old 07-22-2005, 11:37 AM   #1
LQ Newbie
Registered: Feb 2003
Posts: 15

Rep: Reputation: 0
Port Forwarding some ports works some don't

I am working on setting up a firewall to do port forwarding. I am using RH 7.3 and gShield as the firewall script. I currently have port forwarding working for port 3389 and have to get it working for port 5900. I am using the forwards file of gShield and created a rule exactly the same as the one I used for 3389 but for 5900. I can connect to both ports from the servers command prompt using telnet but from outside I can only connect to 3389. Port 5900 is for our vnc program, I have tried changing it to port 6900 which didn't help. Does VNC need any other rules setup like active ftp would or is there any other suggestions on what I can try to help troubleshoot this issue.

Thanks for any and all help

P.S. I have just tried forwarding all ports from 3300-6000 and can still only connect to 3389 and not 5900 don't know if this helps.

Last edited by Sarcha; 07-22-2005 at 11:41 AM.
Old 07-22-2005, 11:46 AM   #2
LQ Guru
Registered: Mar 2004
Distribution: Slackware
Posts: 6,325

Rep: Reputation: 757Reputation: 757Reputation: 757Reputation: 757Reputation: 757Reputation: 757Reputation: 757
You could eventually run
iptables -L -n -t nat show how your iptables go
Old 07-22-2005, 04:03 PM   #3
LQ Newbie
Registered: Feb 2003
Posts: 15

Original Poster
Rep: Reputation: 0
Here is the output of iptables -L -n -t nat

target prot opt source destination
DNAT tcp -- tcp dpts:3300:6900 to:
DNAT udp -- udp dpts:3300:6900 to:

target prot opt source destination
SNAT all -- to:

Chain OUTPUT (policy ACCEPT)
target prot opt source destination

Does that look right? The is the external NIC the internal nic is and the is the internal server things are being forwarded to.


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
IPCHAINS port forwarding and IPTABLES port forwarding ediestajr Linux - Networking 26 01-14-2007 07:35 PM
Simple Port Forwarding Firewall - not forwarding MadTurki Linux - Security 14 04-09-2006 12:08 PM
how to make azureus (or any port forwarding) works in my suse 9.3 box and squid proxy efm Linux - Newbie 0 10-31-2005 01:22 AM
Smoothwall port forward works for some ports, not for others! gwaine Linux - Networking 1 03-21-2003 11:08 AM
IpTables port forwarding works but cant get out acdcbag Linux - Networking 1 11-08-2001 03:48 PM > Forums > Linux Forums > Linux - Networking

All times are GMT -5. The time now is 10:04 PM.

Main Menu
Write for LQ is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Open Source Consulting | Domain Registration