Iptables is a module that provides the Linux operating system functions of firewall, NAT and logging of data traveling over a computer network.

learn more… | top users | synonyms

6
votes
1answer
4k views

How to configure a firewall on Centos using Vagrant and Chef

I've created a server box using Vagrant and Chef and everything is up and running correctly. However, when the box is installed from scratch the default iptables rules are in place and so I need to ...
-2
votes
1answer
27 views

Need a proxy server for only logging requests [on hold]

I have looked at Squid and find it too heavy for the simple task that I have at hand. I just need a proxy to run on Ubuntu, preferably a transparent one, which will only log http requests and nothing ...
2
votes
3answers
3k views

iptables firewall only allows internet traffic if source port of 80 is allowed

I am configuring an iptables firewall, currently just to allow http and https traffic. It is working but under a particularly strange rule - I must allow incoming connections with a source port of ...
2
votes
2answers
1k views

linux: how to run aria2 or wget only through eth0

I have a computer under Linux with several network cards, for example: eth0, eth1, eth2, eth3. Is there some way to run any downloader, like aria2 or wget only through one interface, for example eth0? ...
1
vote
1answer
6 views

iptables limit number of outgoing connections on a port

I'm currently using the following to limit the number of incoming connections on port 9001 to 900. iptables -t filter -I INPUT -p tcp --syn --dport 9001 -m connlimit --connlimit-above 900 -j REJECT ...
1
vote
0answers
7 views

tcpdump capturing packets only when interface is specified

I have tried 3 different ways of capturing a stream of packets coming into my server. Two of them work and the third does not. I am trying to determine why it is missed by the third approach: ...
2
votes
1answer
4k views

DD-WRT firewall rule configuration

I'm using DD-WRT on my linksys router. I want to limit each user on my network to 200 connections at any given time. Does anyone know the rules I enter the firewall in DD-WRT admit panel. I tried ...
1
vote
3answers
3k views

iptables syntax to forward remote desktop requests to a virtual machine on CentOS host

I can rdesktop into a VM running Windows XP hosted on my CentOS 5.4 machine from the hosting machine and work just fine using the private address (192.168.122.65), but I now need to allow remote ...
3
votes
2answers
2k views

How to use iptables to connect proxy server

In my company, all http and https must connect to a proxy server, which means we must set proxy in our web browser. Our department has an internal network (192.168.0.xxx). I use a Linux server as ...
0
votes
0answers
18 views

WordPress won't load unless iptables is disabled

I am running CentOS 6.6 using nginx. WordPress will not load unless iptables is disabled. I tried to add the 9000 port for fastcgi, but that did not work. I am guessing it has something to do with ...
0
votes
0answers
11 views

Use IPTables FORWARD for NFS

I have this topology [R1] -> [F1] -> [Server] I need to pass ssh, web and nfs traffic through F1 to Server using iptables. It's quite easy with ssh and web but I'm stuck with nfs. I have set static ...
1
vote
1answer
15 views

How do I know if certain iptables extensions are available and enabled?

I was reading this: https://help.ubuntu.com/community/IptablesHowTo#Allowing_Established_Sessions It says "If the line above doesn't work, you may be on a castrated VPS whose provider has not made ...
1
vote
1answer
10 views

Confusion about the `conntrack` extension of `iptables`

The iptables-extensions manpage has this to say about the conntrack extension (emphasis mine): This module, when combined with connection tracking, allows access to the connection tracking state ...
0
votes
1answer
2k views

Cannot open port 8080

I'm running a VmWare with an application under JBoss starting up on port 8080. I'm able to access the app from outside the VM if the iptables are off. However, I must turn on iptables due to some ...
0
votes
0answers
28 views

CS:GO SRCDS and iptables (firewall)

I have very strange problem. This morning I wanted download, install and host small server for CS:GO on my VPS. I used this tutorial: ...
1
vote
1answer
12 views

Make traffic go one-way by using iptables

I have a network topology: [C1] - [R1] - [R2] - [C2] C1-R1 network is 192.168.100.0/24 R1-R2 network is 10.9.8.0/30 R2-C2 network is 192.168.200.0/24 What I need to do is to make C2 be able to ...
0
votes
0answers
6 views

Port Forwarding using iptables

I have the following problem: I have two servers. I can connect to server A trough the internet. But I also want to connect to server B. How can I use iptables, that if I connect to server A over ...
0
votes
1answer
25 views

Where do port knocking services listen for incoming knocks?

I'm trying to understand how a port-knocking daemon is able to monitor for knocks, independent of the firewall rules (e.g. accept/drop/reject packets). I've installed knockd, which listens for lets ...
3
votes
2answers
192 views

SSH reverse tunnel into Docker container

I need to xdebug something that fails on the server in a docker container and from my laptop I have ran ssh -R 9000:localhost:9000 server and verified the tunnel by telnet localhost 9000. So far so ...
0
votes
0answers
11 views

Limited network connectivity when SSHing through an OpenVPN tunnel

I have setup an instance of OpenVPN with a public IP to allow access to a private subnet on Amazon EC2. I am able to SSH onto machines on the private subnet through OpenVPN but when I do I have ...
1
vote
0answers
96 views

Configuring iptables for guest WLAN in DD-WRT

I'm constantly failing to get a guest WLAN in DD-WRT working. I can connect to the second SSID and get an IP address of the second DHCP server range. But I cannot connect to the internet. I followed ...
0
votes
0answers
14 views

How to redirect traffic to a fixed IP address in Fwbuilder

I'm new to fwbuilder and I want to redirect all incoming wifi traffic to my web server. I tried many iptables command but I've failed so I came up to GUI firewall. Can anyone suggest how to do it?
1
vote
1answer
117 views

Connecting my Xbox 360 to my Raspberry Pi 2 to use an OpenVPN connection

Here is my brief setup: Xbox360 Raspberry PI 2 running ArchLinuxARM (alarm) The raspberry pi's main ethernet port has a cable connecting directly to my main router The xbox has a cross-over cable ...
0
votes
0answers
16 views

Manage NAT using a tool

I have a Raspberry Pi on which I had previously installed Raspbian and am now installing another version on again. It is mainly used to be a test maschine for small programs and primarily as a NAT ...
3
votes
4answers
2k views

bridge does not forwarding packets centos

I am using CentOS 6.5 64 and use xen to create a virtual machine (CentOS) ifconfig [root@CentOS ~]# ifconfig eth0 Link encap:Ethernet HWaddr 08:00:27:54:B3:FA inet6 addr: ...
0
votes
0answers
16 views

OpenVZ cotainer and NAT

I have been trying to days to solve my NAT issue with OpenVZ. I have used their guide on their website/wiki, however I just seem to be unable to get it to work. My Linux box is running on CentOS 6 ...
0
votes
1answer
13 views

iptables: Routing requests to localhost:8080 to google.com

I am trying a simple routing rule that would forward the requests to localhost:8080 to some external address (ex google). I added the following rule : sudo iptables -t nat -A PREROUTING -p tcp -d ...
0
votes
0answers
13 views

Guest as Virtual machine connection to Host

I have guest run on my machine on qemu with configuration: /usr/local/kvm/bin/qemu-system-x86_64 -enable-kvm -cpu host -smp 8 -hda ${TEST_VIRT_ENV_IMAGE} -m 4096 -netdev user,id=user.0 -device ...
3
votes
2answers
3k views

What does an empty iptables mean?

I’m using CentOS and when type in the following iptables command: iptables -L -v The output is as follows: Chain INPUT (policy ACCEPT 19614 packets, 2312K bytes) pkts bytes target prot opt in ...
0
votes
0answers
23 views

Forward all traffic from one Linux interface to another?

I have a virtual ESX interface "eth1" that I want to act as a gateway for connections, and then route all of the traffic from these connections out of my "eth0" (WAN) interface. Here are my ...
0
votes
2answers
54 views

Traffic redirection with Rasperry Pi router

I use a Rasperry Pi (running raspbian) as a wi-fi router. It redirects traffic from the Ethernet wire (eth0 - wire + ppp0 - L2TP connection, lx2tp used for it) to wlan0 (USB wi-fi dongle, hostapd used ...
3
votes
1answer
2k views

Allow access from outside network with dmz and iptables

I'm having a problem with my home network. So my setup is like this: In my Router (using Ubuntu desktop v11.04), I installed squid proxy as my transparent proxy. So I would like to use dyndns ...
0
votes
0answers
27 views

Tor Middlebox: How to check if there is a DNS leak?

I created a tor middlebox. Laptop plus WLAN. Creates a WLAN AP all traffic from that AP should be routed into tor. But I am not sure, if the DNS requests are not leaked. How can I check that? This ...
0
votes
1answer
66 views

ssh: connect to host * port 22: Connection timed out

I have CentOS 7 running on a VPS machine and after a computer restart, I could no longer SSH to it. $ ssh -v <IP> OpenSSH_6.6.1, OpenSSL 1.0.1e 11 Feb 2013 debug1: Reading configuration data ...
0
votes
0answers
31 views

tor middlebox: How to route traffic through a socks proxy automatically? iptables routing wlan

I built a tor middlebox. It is an old laptop without screen, creates a WLAN and every traffic on that WLAN is routed into tor. my iptables script: iptables -t nat -A PREROUTING -i wlan0 -p udp ...
0
votes
0answers
24 views

Connecting router traffic to sshuttle tunnel

I am using sshuttle to get cleanly out of a questionable hotel wifi connection. I have a little travel router and would like to use it as well, briding my laptop's sshuttle connection so I can connect ...
0
votes
0answers
32 views

CentOS as home network router: IPTables Port Forwarding failure

I have currently set up a home server with a CentOS 6.6 installation on it. The server has two NIC interfaces which I'm using it as my router and DHCP server. Here's a diagram showing the network ...
0
votes
0answers
20 views

NAT Rule for PPTP Port Forwading

I'm under a very heavy firewall where only very common ports such as 21 and 80 are open. I installed PPTP on my own dedicated server (a Debian Linux) and I`m trying to connect it using Windows, but ...
0
votes
0answers
11 views

https proxy setup in NAT-ed clients

I have network setup as follows: I have 2 PCs. A and B. A is connected to Internet, and A and B is connected by local network. B can also connect Internet through A by NAT setup. In A, the NAT setup ...
0
votes
0answers
15 views

Create a VPN tunnel from ethic to wlan0

I have a lan network of which all internet traffic has to be routed through a openVPN tunnel. I use a RPi, and have setup ethic with a DHCP server, and can connect clients. Currently I use a lan0 to ...
0
votes
2answers
26 views

iptables default rules understanding

What does the last part in the following rules means in term of traffic that is allowed in (dtp:domain, bootps) ? From my research I understand that bootps is bootstrap and dpt is destination port but ...
0
votes
0answers
16 views

IPTables and SIP Proxy-Authorization Header

Is it possible for iptables to check SIP packets for Proxy-Authorization headers, and if there's more than one header in a SIP packet, modify the packet so only the latest Proxy-Authorization header ...
0
votes
0answers
102 views

Output port redirect with firewalld?

I'm used to iptables and I can't find a way to do this with firewalld. I need to redirect the output traffic of one port back inside in the same port, basically this: iptables -t nat -A OUTPUT -p tcp ...
0
votes
0answers
36 views

port forward from host to libvirt guest virtual machine that is bridged to the host nic

I am having no luck getting access from the outside to a http server running on my network in a Debian virtual machine that was created through libvirt. This what my network looks like: PC1: running ...
0
votes
0answers
38 views

Forwarding some ports and websites from “eth0” to “wlan0” with IPTables

I have eth0 and wlan0 devices in my work laptop. eth0 access the company's network and it comes with the whole firewall rules and so on. So I’m unable to use Skype, Google Hangouts and other things I ...
0
votes
0answers
42 views

Set up port forwarding on Ubuntu with ufw

I want to route HTTP traffic from port 80 to port 8080. I added the following rule to /etc/ufw/before.rules -A PREROUTING -p tcp --dport 80 -j REDIRECT --to-port 8080 But it works only if direct ...
0
votes
0answers
44 views

iptables - How to mirror all ports from one IP to a single port on another IP

I would like to set up IP tables on my router to mirror traffic on all ports from 192.168.1.30 and send it to 192.168.1.10:5860 I think I need to combine the two commands below, but I'm at a loss. ...
1
vote
0answers
90 views

DDWRT - Virtual Interface - firewall command - RDP

I have DD-WWRT flashed on my Linksys e2500v3 router. I added virtual interface to create a guest wifi network that would have access to the internet, but not to the private network or router. At ...
0
votes
0answers
19 views

How to see who's blocking my internet connection? fail2ban?

I was just running apt-get dist-upgrade from a distant ssh console when I lost the connection. I would like to know which service blocked my connection. I know fail2ban is sometime a bit flaky, but ...
11
votes
2answers
10k views

No idea what is listening on port 80 in OS X

I'm on OSX Mountain Lion 10.8.3, and I've freshly rebooted my Mac. I want to start a service (like Apache on port 80), but there is already something going on with port 80: telnet localhost 80 ...