TCP/IP Port Redirection

TCP/IP Port Redirection

Post by Erich Webe » Sat, 23 Jan 1999 04:00:00

Hi Luke!

If you configured Firewall with Linux you can set the <FW_REDIRECT> in the
The variable contains a list of tripels which have the following format:

local port, target ip, remote port

I think the fcii daemon (firecracker) does this job. But I think it uses
ipfwadm to do it..



Quote:>I was wondering if there is any way to redirect a local TCP/IP port to a
>remote host's port.  For instance, I want to connect my Windoze news reader
>to it's server, but it runs through my Linux box with a proxy. If I could
>specify my Linux box as the server and forward the connection to a remote
>host, it would be perfect.  I thought there was a way to do this without
>ipfwadm, and ideas? Thanks!


1. PLS-Major Problem in LAN (natd, IP alias, Port and IP redirections)

PLS tell me what to do, because I am in great need!!!

-=Short=-: My FreeBSD server (running natd for other machines) looses the
internet connection (every ~hour) and the message "ping: sendto: No buffer
space available" appears if I ping my internet gateway.

During the weekend I changed my lan and I put a fbsd server to act as a
masquerade server/firewall/router.

I had already 15 IP addresses and thus I put 15 alias command in my rc.conf
for the vr0 interface.

Also I run natd daemon for my internal ( lan.
I redirect one IP to an internal IP, and some tcp & udp ports to some
machines on my NET.

All were working and tested. But my problem starts here.......

After 1 hour or less all the machines from my internal net (windows, Linux,
hp) are unable to ping outside the net, and tracert from windows (from my
internal lan) says

Reply from Source quench received.

Other traceroutes just print * after my server

From my router I ping the next gateway and I see that FreeBSD

ping: sendto: No buffer space available

and you can't do anything else..

(What is buffer space???)

After a lot of experiments I found that if I do an
ifconfig vr0 down
ifconfig vr0 up

the problem is solved (temporally).

So I have to ping all the time my gateway in a terminal window, and when I
see the message

ping: sendto: No buffer space available

then I have to issue the ifconfig vr0 down and ifconfig vr0 up.

Just for the info. My router system is a Pentium 200MMX / 32 MB RAM, FreeBSD
release 4.4 and all this time as a single host had no problem. and for my
network card:
vr0: <VIA VT6102 Rhine II 10/100BaseTX>. My total traffic of the internet is
usually < 200 KB/sec

PLS PLS PLS. I am in great trouble because I am in charge of over 20
machines here and all the people get frustrated when the internet connection
breaks up. PLS any suggestions?

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