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

4
votes
1answer
617 views

Block all outgoing traffic for a User running Wine apps

Good day, I'm using a lot of WINE apps under Linux which work just fine, but one thing I am specifically looking for right now is to block their access to the internet (outgoing), with exception of ...
4
votes
0answers
234 views

Iptables error :libipt_cgroup.so doesn't exist while using net_cls.classid in net_cls cgroup subsystem

In kernel document doc/cgroup/net_cls.txt, it introduces the function of net_cls.classid, and show an example of netfilter (iptables) using this tag to perform actions. the command of iptables is: ...
4
votes
0answers
3k views

Route outgoing VPN traffic through local transparent proxy

I have a Digital Ocean droplet (similar to an Amazon EC2 instance) running Ubuntu Server 12.04.3 x64 with both strongswan 5.1.1 (built from source) and squid 3.4.2 (also built from source) installed. ...
3
votes
4answers
3k views

iptables - add rules not as root

One of our servers is being hit daily by a large number of spam bots. They're not able to post any spam, but they still try and end up slowing down the server for real users. To counter this, I have ...
3
votes
5answers
15k views

iptables: Allow only HTTP access for web browsing

Have a linux box, want it locked down but just be able to surf internet on it. Why is this script blocking http too? #!/bin/sh # # iptables -F # #Set default policies for INPUT, FORWARD and OUTPUT ...
3
votes
4answers
5k 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: fe80::a00:...
3
votes
1answer
360 views

Allow shell access for key holders OR password login for whitelisted IP addresses

As a first line of defense against brute-force attacks, I've restricted SSH login attempts with TCP wrappers (denying access by default, and maintaining an IP whitelist in /etc/hosts.allow). However, ...
3
votes
2answers
6k views

iptables gives me the error “can't initialize iptables NAT”

I am trying to use iptables and it is giving me the following error root@vikkyhacks:~# iptables -t NAT -L iptables v1.4.18: can't initialize iptables table `NAT': Table does not exist (do you need to ...
3
votes
2answers
5k views

unable to connect to localhost:80 after installing nginx

I just installed nginx by doing sudo yum install nginx and I'm unable to connect to it on port 80. I tried stopping iptables by doing sudo service iptables start and was still unable to connect. I'm ...
3
votes
1answer
559 views

Why small TCP connections succeeds, but big ones fails?

Sometimes from Linux system I see the following weird behaviour: I able to ping things and sometimes use some services, but networking is very bad. For example, now I routed connection through my ...
3
votes
2answers
55 views

IPTables - Redirect traffic based on country

Is there any way how to allow TCP traffic only from specified countries on a specified port and the rest of traffic redirect to another IP/port using iptables ?
3
votes
1answer
33 views

Is IPTABLES obsolete when behind a router?

I'm still quite noobish when it comes to networking. I was fiddling around with squid on centos and i was wondering whether turning on iptables when your centos box is behind your isp modem/router has ...
3
votes
2answers
2k 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? ...
3
votes
1answer
910 views

How to isolate networks with a Mikrotik router?

I have recently got a Mikrotik router for my network, and I want to create 3 networks that are isolated from each other but all have internet access: The "main" network for PCs, etc. A network for ...
3
votes
1answer
2k views

Two NICs on the same subnet but with different networks?

Description This is similar to this question, but different: Linux computer has two NIC. eth0 is statically assigned with an IP. eth1 is assgiend by personnel in the field which could be same IP or ...
3
votes
1answer
295 views

iptables on openwrt router: logging connections to a host from clients on the same subnet

I am trying to setup an auto wake-on-lan setup using my router that is running OpenWRT 14.07, Barrier Breaker. My idea is that the router monitors any connection attempts to the host I want to wake up ...
3
votes
1answer
179 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 ...
3
votes
2answers
1k 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 ...
3
votes
2answers
6k views

Apache runs locally but can't be accessed from other machine

I'm running Apache 2.2.3 in a VM for a test environment on CentOS 5. Apache is running and responding to requests on the VM itself. If I run "lynx localhost" on the VM I do get my test page. When I ...
3
votes
2answers
3k 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 ...
3
votes
1answer
109 views

Use port forwarding with masquerade

I'm using a debian as a router with nat configured. How can I set up port forwarding, to set an rdp server on the local network for example?
3
votes
2answers
238 views

Blocking ports with iptables

I have a server with multiple interfaces (IPs). I'd like to block all ports on one of the IPs (I don't want to change anything for other IPs/interfaces), but allow outgoing connections from it. For ...
3
votes
1answer
306 views

Allow only one website using iptables in a linux router [duplicate]

I have a Linux server I'm using as a router for my internal network. I need to block all the websites except one or two using iptables. How can I set this up?
3
votes
2answers
13k views

How to permanently disable firewall in Red Hat Linux

I have followed the below steps to disable the firewall in Linux. After reboot, again firewall is enabled. How to disable firewall permanently? Login as the root user. Next enter the following three ...
3
votes
1answer
6k views

How do I forward traffic between Tun device and eth0?

In summary, I would like to have Tun device traffic forwarded back and forth through another network interface that has internet connection. While I can see the traffic going out to internet and ...
3
votes
2answers
688 views

Force certain applications to use VPN

For a few days now, I've been trying to force only certain applications to use a VPN. I've thus far found it pretty simple to either force all applications to use it, or no applications to use it. I'...
3
votes
1answer
6k views

Redirect incoming https to local ip with iptables

I have a router with 1 network interface (eth0, public ip) and an alias for eth0:0, local ip 192.168.1.1. I want to redirect all incoming https (443) traffic to another server. I tried it with ...
3
votes
1answer
1k views

iptables status enabled after restart even after disabling

I am disabling iptables on Oracle Linux 6 with these commands. setenforce 0 service iptables stop service ip6tables stop chkconfig—level 123456 iptables off chkconfig—level 123456 ip6tables off ...
3
votes
2answers
2k views

How to test IP Tables Rule (Linux Ubuntu12.04)

I wanted to ask how to test IP Table Rules. For example, I have a port number and I want to be sure that it accepts all packets. How can I do it? After I type iptables -L I see that the rule has been ...
3
votes
1answer
2k views

IP forwarding on the same network

I have a raspberry pi that I have put wifi on. I am also using its ethernet connection to bring internet to my XBox 360. I want to bridge these connections AND keep them both on the same network. For ...
3
votes
2answers
5k views

How to blacklist IPs on Windows 7?

I'm trying to find something similar to iptables in Linux for Windows. I've tried using Windows firewall as well as editing the host file to block specific IPs, but had no success. I've also tried ...
3
votes
1answer
3k views

Properly portforwarding the external IP with iptables

I am trying to forward all the incoming internet/LAN requests on port 80 to my local machine (running Apache), current iptables work (forward incoming internet traffic to my desktop, but if I try to ...
3
votes
0answers
15 views

VPN connection problems regarding plex media server and voice over IP

I have a home server - running Debian Jessie and plex media server. My router (fritzbox) allows all smartphones in my LAN to receive incoming landline calls (due to a certain app). This part works ...
3
votes
0answers
129 views

Why do different users get different IP via the same interface

On the same server, on root, I am getting the correct internet ip of the interface root@server:~# curl -s --interface ppp0 ipcheck.com 111.111.111.111root@server:~# However... If it's not super ...
3
votes
0answers
38 views

How can I read out the value of internal counter inside IPSet

I know there is an option named “counters” when creating an IP set with IPSet. However, I want to know how to read the value of the counters out, so as to know how many packets or how much data has ...
3
votes
4answers
3k views

IP forwarding from one interface to another on Debian 7

Background The Debian 7 that I run has the following interfaces wlan3 == Internet connection 85.5.48.64/24 wlan2 == act as an AP (hostapd) 192.168.5.1/24 I run the following settings on the ...
3
votes
1answer
1k views

Linux iptables forward from ip1:port1 to ip2:port2

I connect thought tunnel to other machine like this: ssh user@ip -L2000:192.168.64.88:80 So on my local machine I want to configure iptables that way like I have a "native" access to 192.168.64....
3
votes
2answers
6k views

Using iptables SNAT based on source interface and ip address

I would like to change source ip address according to ip address and interface it came in. Let's consider following example: ----------------------------- | | | ...
3
votes
1answer
3k 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 ...
2
votes
1answer
9k views

iptables duplicate traffic to another ip

This blog post has a template iptables rule to forward traffic, to and from the router to another ip address. iptables -t mangle -A POSTROUTING \ -d [IP to spy on] \ -j ROUTE –tee –gw [...
2
votes
1answer
446 views

What other ports should I block to maximize server security? PS using IPTABLES

I have blocked ports 80, 9001, 9080. What other ports should be blocked to maximize security? PS: It is a asterisk server / PBX Sorry: New Systems Admin here :) Thanks!
2
votes
2answers
545 views

Why after Accepting Ports 20 and 21 in iptables are they still closed?

I am trying to open the FTP Ports on my server. I have vsftpd installed on the server already. However I am unable to reach the server on ports 20 and 21 Somehow it is allowing me to access port 21 ...
2
votes
2answers
327 views

Why put ACCEPT target after DROP in iptables?

My iptables -nvL looks like this: bash# iptables -nvL Chain INPUT (policy ACCEPT 1031 packets, 81085 bytes) pkts bytes target prot opt in out source destination ...
2
votes
1answer
3k views

Can ping but can't connect (curl, wget, apt-get, etc.) (rasberry pi server)

Background: I am trying to set up a rasberry pi server. Everything was going well and my pi could apt-get update etc, until I got the port forwarding to work and ssh to work outside of the LAN. I ...
2
votes
2answers
2k views

How to route the incoming connections through a specific interface?

I have multiple ethernet cards with two different set of networks configured on them. The output of route -n is given here:: Kernel IP routing table Destination Gateway Genmask ...
2
votes
1answer
3k views

Will increasing number of rules in iptables slow down my internet

How much impact will the rules have on speed, if we are using match to queue the packets.
2
votes
2answers
9k views

iptables - How to forward all external ports to one local port

I want a service to be running on every external port on my system. Since it wouldn't work to start 65535 single instances of that service (I guess...) I thought of using iptables for this. The ...
2
votes
1answer
194 views

Secondary NIC: what all can I do?

I was loaned a NIC which I promptly installed in my F16 workstation just to 'play' with it (using iptables and stuff). Other than forwarding packets from the new NIC to the old NIC using various ...
2
votes
5answers
10k views

Home network to accept only certain MAC addresses from LAN

I have Ubuntu 10 as router with WAN(eth0) and LAN(eth1). How can I restric eth1 to accept only packets from certain MAC addresses and drop the rest? I am also about to setup DHCP to certain MAC ...
2
votes
2answers
28 views

Blocking a device from all network traffic, but with specific exceptions

I have a router that runs Tomato, so I have access to iptables. There's a device on my network with an IP address of 192.168.1.100. I don't want it to send data to the Internet except for a very ...