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.

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76
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18answers
126k 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: ...
13
votes
4answers
19k 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?
13
votes
3answers
24k 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 ...
12
votes
5answers
10k 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 ...
11
votes
3answers
13k 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 ...
9
votes
2answers
23k 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 ...
9
votes
5answers
7k 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 ...
9
votes
1answer
1k 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 ...
8
votes
1answer
4k 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 ...
7
votes
4answers
3k 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: ...
7
votes
2answers
849 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 ...
6
votes
2answers
21k 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 ...
6
votes
1answer
10k 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 ...
6
votes
1answer
1k views

How can I redirect all UDP traffic from one port to another on BSD / OS X?

On Mac OS X 10.9.5 I am running boot2docker and would like to temporarily forward a non-privileged UDP port 69 to port 69 of the boot2docker virtual machine. Virtualbox only supports forwarding ...
5
votes
1answer
2k 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 ...
5
votes
2answers
17k 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 ...
5
votes
1answer
2k 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 ...
5
votes
3answers
14k views

SSH tunnelling with multiple dynamic port forwardings

I am trying to monitor multiple JVMs running on different servers through an ssh tunnel. Thanks to one of the UNIX gurus here, I have managed to get this running for a single server by: Run jstatd ...
5
votes
3answers
4k 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 ...
5
votes
2answers
1k 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
176 views

port forwarding to application in network namespace with vpn

I was able to set up a network namespace, establish a tunnel with openvpn and start an application that uses this tunnel inside the namespace. So far so good, but this application can be accessed via ...
5
votes
2answers
1k 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 ...
5
votes
3answers
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 ...
4
votes
1answer
588 views

What does port forwarding mean in “SSH port forwarding”?

Wikipedia says In computer networking, port forwarding or port mapping is an application of network address translation (NAT) that redirects a communication request from one address and port ...
4
votes
2answers
3k views

SSH connection refused from inside my LAN

I'm on Fedora 19 and I have a problem with ssh. Ssh is up and running and I can connect when I enter my lan ip. But when I try my server name (blahblah.no-ip.org) I get a connection refused. No-ip is ...
4
votes
1answer
2k 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

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
2answers
6k 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 ...
3
votes
1answer
1k 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
1answer
214 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
1answer
61 views

What ports need to be open on a firewall to access the internet?

Let's say as the example that I have a firewall that blocks ALL ports from all sources/destinations. What ports would I need to open to be able to successfully run: ping google.com ...and are ...
3
votes
2answers
948 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
1answer
541 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
3k 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
328 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
83 views

Tunneling multiple ports through a single port [duplicate]

I'd like to forward several ports from my local machine to a remote machine through SSH tunneling. However, I want this to happen across a single port. Is there a protocol or tool that can multiplex ...
3
votes
1answer
535 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
1k 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
0answers
411 views

SSH Failing to fork with sshpass

I've a problem with port forwarding command using sshpass. Problem is that it's working on one server and does not work on another. Both are Debian 7 x64 boxes. sshpass -p password ssh -f -D ...
3
votes
1answer
257 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
2k 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
2k 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
2answers
239 views

Cannot connect to localhost on port 4430

I am running vagrant from a virtual box with CentOS and Nginx installed. I've created a reverse tunnel from the vagrant box to a remote server but when I am trying to connect to my localhost on port ...
2
votes
1answer
493 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
413 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
4k 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
70 views

ssh port forwarding without logging in

I am forwarding a port of a remote server to my local mac as follows: ssh -L 15672:localhost:15672 me@example.com When I do this in a shell, I am also logged into example.com. Yet I would like the ...
2
votes
1answer
3k 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
568 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
446 views

Local port is not accessible with public IP address

I have a linux server which has public IP and Private IP. So, when ever I login with public IP, the terminal directly shows private IP. example: $ ssh root@55.27.XX.XX root's password: ...