Port forwarding is a process consisting in the translation of a host:port couple into another host2:port2 couple, both submitted to the same network mask.

learn more… | top users | synonyms

41
votes
13answers
60k views

SSH tunneling error: “channel 1: open failed: administratively prohibited: open failed”

When I open this ssh tunnel: ssh -nXNT -p 22 localhost -L 0.0.0.0:8984:remote:8983 I get this error when trying to access the HTTP server running on localhost:8984: channel 1: open failed: ...
8
votes
1answer
452 views

How can I limit ssh *remote* port forwarding?

I need to limit which ports can be remotely 'ssh -R' forwarded by an user. I know about permitopen option on authorized_keys, but as it says on man page it only limits local 'ssh -L' port forwarding ...
7
votes
2answers
4k views

ssh port forward to access my home machine from anywhere

http://serverfault.com/questions/303937/how-to-make-freebsd-box-accessible-from-internet I want to understand this whole process of port forwarding. I read so many things but failing to understand ...
7
votes
1answer
1k views

Forward all ports SSH

I have a question about SSH/Port forwarding. I haven't found the solution anywhere and don't know if there is any. I have a server behind my NAT box at home. I have port forwarding from my NAT box to ...
6
votes
4answers
2k views

How to debug SSH port forwarding

This is an extension to ssh port forward to access my home machine from anywhere I tried things mentioned there but I am not able to ssh to my machine. Netgear router settings for port forwarding: ...
6
votes
1answer
196 views

Determine dynamically allocated port for OpenSSH RemoteForward

Question (TL;DR) When assigning ports dynamically for remote forwarding (a.k.a. -R option), how can a script on the remote machine (for instance sourced from .bashrc) determine which ports were ...
5
votes
2answers
753 views

How can I forward traffic from my publicly available server to a computer that is not publicly available?

My home computer is behind an ISP-level NAT which does not allow me to host game servers as a result. I have a VPS which I use as a web server. I want to host a game server of Minecraft, but the VPS ...
5
votes
1answer
99 views

Why does ssh -g say that address is already in use?

I setup an SSH connection with port forwarding that allows remote hosts to connect to the local forwarded ports like this: ssh -g -L 5115:localhost:5115 <server> The connection works fine ...
4
votes
4answers
124 views

List ports a process PID is listening on (preferably using iproute2 tools)?

I'm looking to list all ports a PID is currently listening on. How would you recommend I get this kind of data about a process? NOTE: I was surprised I could not easily find an answer to this!
4
votes
1answer
1k views

ssh tunneling a local display to another server

I have a GUI test stand simulation connected to some hardware that is under test. The test stand is a Sun Sparc Ultra 2 SunOs 5.7. The simulation software checks to see if your running your display on ...
4
votes
1answer
1k views

Can sshd restrict client tunnel endpoints to localhost?

Normally an ssh client can request TCP forwarding using the -L command line option. The server can disable this completely using AllowTcpForwarding no. If enabled, the client can request to connect ...
4
votes
2answers
8k views

Port forward to VPN Client?

I've run into a bit of a puzzle and haven't had much luck finding a solution. Right now I am (sadly) connected to the net via Verizon 3G. They filter all incoming traffic so it is impossible for me to ...
4
votes
1answer
895 views

SSH Port Forward a local IRC server to my remote server

So, I have this slight dilemma: I am not allowed to host an IRC server on my VPS, but I am allowed to use tunneling of some sort to let users connect to an IRC server I have set up locally on my Mac ...
4
votes
1answer
1k views

How to check if port forwarding is enabled?

I have just set up a DNS server for my own network, and many guides online suggest to make sure that port forwarding on port 53 is not enabled. The thing that is not clear to me is this: should I ...
4
votes
2answers
5k views

How to forward a port from one machine to another?

Consider the following situation: At my home, I have a router (which is connected to internet), server (S) and my main machine (M). S is reachable from the internet (it has static IP), and it is up ...
4
votes
2answers
7k views

How can I redirect outbound traffic to port 80 using iptables locally?

I'm trying to locally redirect ports on my Ubuntu machine using iptables. Similar to transparent proxying. I want to catch anything trying to leave my system on port 80 and redirect it to a remote ...
4
votes
2answers
1k views

iptables port forwarding

I have a CentOS server with Java/J2EE(Tomcat) installed on TCP port 8080. I have two interfaces, eth0 and lo. I need to forward all incoming connection on TCP port 80 to 8080. I tried doing the ...
4
votes
2answers
1k views

Port fowarding and load balancer in ubuntu server 12.04

I am looking to create a load balancing server. Essentially here is what I want to do: I have a public IP address, lets say 1.1.1.1 I have a second public IP address, lets say 2.2.2.2. I have a ...
3
votes
1answer
632 views

tc class rate 50Kbps != 50K/s in wget?

Got the following test rule setup: tc qdisc add dev wlan0 root handle 1: htb tc class add dev wlan0 parent 1: classid 1:1 htb rate 1000Mbps tc class add dev wlan0 parent 1:1 classid 1:5 htb rate ...
3
votes
3answers
1k views

Simple way to create a tunnel from one local port to another?

I have a development server, which is only accessible from 127.0.0.1:8000, not 192.168.1.x:8000. As a quick hack, is there a way to set up something to listen on another port (say, 8001) so that from ...
3
votes
2answers
486 views

SSH access from inside and outside a LAN using the same terminal command

I have a Raspberry Pi (RPi) and I am making remote connections to it using ssh. I have managed to set up ssh correctly such that I can access the RPi both from a local area network and from the ...
3
votes
5answers
164 views

Securely tunnel port through intermediate host

I'm looking to route a port for VNC back to my house here. I have to jump over a single host to then hop to my actual work machine. sittinghere will be my local home machine hopper will by the ...
3
votes
1answer
117 views

sshfs LocalForward without config file

I'm trying to add portforwarding to my sshfs-mount-scripts: sshfs tim@devserver1:/ /home/tim/mnt/devserver1/ -o SSHOPT=LocalForward 127.0.0.5:3306 127.0.0.1:3306 So far I've failed using the ...
3
votes
2answers
337 views

SSH through router to internal file server

This is a real beginner question, I know. But I really don't seem to be able to wrap my head around the terminology to get what I want working. And since I want to do this on a router that 40-50 ...
3
votes
2answers
4k views

iptables redirect outside requests to 127.0.0.1

I have a service running on 127.0.0.1 with port 2222. I need to forward all requests to 192.168.2.2:2222 (outside IP) only from subnet 192.168.1.0/24 to 127.0.0.1:2222. I'm trying to use this, but ...
3
votes
1answer
241 views

listen to a conversation using port forwarding

I have been able to make a phone calls using the SIP client Pjsua from one Linux computer to another one. In case you have not heard of this user agent, explaining it's functionality is quite easy. It ...
3
votes
1answer
1k views

How to parameterize the LocalForward option in ssh_config?

I'm starting with this fully working ssh command: $ ssh -fNL 3306:localhost:3306 coolio@database.example.com This config gets me part of the simplification I am after: Host tunnel HostName ...
3
votes
1answer
290 views

Setting up the firewall for amule on OpenBSD 4.7 gateway

I'm trying to properly setup the firewall on my gateway (OpenBSD 4.7) using pf to allow amule (on 10.0.0.104) to operate properly as discussed here: Now I know pf has changed a bit from OpenBSD 4.7 ...
3
votes
1answer
330 views

Tunnel AFP over SSH over Internet

I can't seem to figure out how to connect to AFP over SSH. Here is my setup: [Raspberry Pi] <---> [router] <---> (Internet) <---> [Client] I'd like to be able to connect to my ...
3
votes
1answer
867 views

Set up password-less SSH tunneling from home computer behind NAT to inside computer behind gateway

My home computer is behind an ISP-level NAT (and firewall). The target computer is work computer behind gateway. You have to log to gateway computer first via SSH (as it is the only one visible and ...
3
votes
1answer
206 views

IPFW Port Forwarding

This is my situation: I want to connect to an OpenVPN server from my office (we're using a proxy, only ports 80 and 443 are allowed). Server IP address is: 176.31.250.232:843 My static IP address ...
3
votes
0answers
1k views

The right way for dynamic ssh port-forwarding

Want my Firefox could use localhost:9099 proxy forwarded from vps server, why it doesn't it work this way? I always get bind: Address already in use $ ssh -vfND 127.0.0.2:9099 vpn OpenSSH_5.9p1, ...
2
votes
2answers
496 views

Port forwarding and masquerading

What is the relationship between port-forwarding and masquerading? If server A is configured to masquerade its clients, and client B accesses the Internet through server A, then since client B is ...
2
votes
1answer
359 views

SSH Setup - How will the router know my computer's ip?

I'm very new to the networking side of the house and am trying to set up SSH on my new Ubuntu machine. I have my DD-WRT router working with DDNS now and can log in to the router page -- but I'm not ...
2
votes
2answers
112 views

Temporary redirect ports

I need a temporary redirection of some ports to another machine. I've tried: iptables -t nat -A PREROUTING -p tcp --dport 4321 -j DNAT --to-destination 192.168.121.4:80 But shorewall blocks all ...
2
votes
1answer
466 views

How to setup port redirection after a ssh connection has been opened?

I'm using openssh on both client and server. I know I can run ssh -L or ssh -R to setup some port redirections over ssh. However, since they are command-line parameters, such redirections must be ...
2
votes
1answer
2k views

Testing if a port was forwarded correctly in Ubuntu

I have a Ubuntu box connected to a wifi router. This wifi router is connected to a d-link adsl modem/router. I am preparing this Ubuntu box to run a server that will use some special ports in UDP and ...
2
votes
1answer
2k views

Port Mirroring using iptables - copy all traffic among nginx on :80 and apache on :8080

I have nginx running on port 80 and apache running on port 8080 I want to transfer all the traffic to both nginx and apache asynchronously i.e the performance of one server wont be dependent on the ...
2
votes
3answers
460 views

Servers running from chrooted Ubuntu on HP TouchPad? [closed]

The problem: servers appear to be broken inside my Ubuntu chroot. No matter what kind of server I try to run, they all seem unresponsive (VLC server won't respond to client, mkRemote doesn't move the ...
2
votes
1answer
88 views

In iptables, what is the difference between targets DNAT and REDIRECT?

More specifically, is -A PREROUTING -i $INT -p $PROTO --dport $PORT -j REDIRECT --to-ports $NEWPORT equivalent to one or both of these? -A PREROUTING -i $INT -p $PROTO --dport $PORT -j DNAT ...
2
votes
2answers
127 views

Allow multiple remote connections to an ssh Dynamic forwarded port

Let us assume I have three machines A - Server to which I am sshing to B - Client from which I am sshing C - Another Client in B's subnet Now, I set up dynamic port forwarding for port 1235 by ...
2
votes
2answers
2k views

Redirect requests to my external IP/port to an internal IP/port?

I have a dedicated server running KVM virtualization with n public IP addresses dedicated to n-1 web-facing virtual machines. Now I'd like to set up some web-facing VM's that don't have a dedicated ...
2
votes
1answer
192 views

SSH Connection into LAN without port forwarding?

I'm living inside a study union for the next few month. the organisation has its own network and gateways where the students are connected to the internet. problem: I don't have access to the routers ...
2
votes
1answer
1k views

Local port forwarding automatically configured on boot?

I have software which needs to run as a non-root user, but needs to listen on port 80 and 443. With iptables, this isn't all that difficult: sudo iptables -t nat -A PREROUTING -i eth0 -p tcp ...
2
votes
1answer
82 views

Forwarding packets from loopback interface with policy-based routing

I have the following iptables rule: iptables -t mangle -A PREROUTING -p udp -m udp --dport 10000 -j MARK --set-xmark 0x4/0xffffffff which sets fwmark 4 on all udp packets with destination port ...
2
votes
1answer
590 views

Port Forwarding using iptables on Open-Mesh

A quick overview for those who are unfamiliar with Open-Mesh: The system uses small wireless access points that automagically build their own mesh network. As long as one of the access points is ...
2
votes
0answers
12 views

SSH fork kills connection

I am using a linux script which has the task of forwarding control of the system to remote support. In this script one of the commands is a ssh port forward command that will forward the port of the ...
2
votes
1answer
116 views

Redirecting an active port

Environment: Web server that requests pages on a specific port from an application server. Problem: If a page request comes into the application server during the restart of a certain web application ...
2
votes
0answers
245 views

Port Forwarding Between 2 Internet Machines

Here's my scenario: Setup There are 3 machines: A: on the internet : has ip (a.a.a.a), has port pa open B: my server / gateway : has ip (b.b.b.b), has port pb open C: on the internet : has ip ...
2
votes
1answer
171 views

WHOIS over SSH via specific port

Is it possible to issue WHOIS requests via my local machine over a port other than 43 to a remote box to execute? Ideally, I'm using Jsch and I'd like to be able to round-robin these requests. I've ...