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

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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 ...
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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 ...
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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. ...
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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 ...
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How do I configure DD-WRT to forward IPSec traffic to an internal server to support a road warrior configuration?

I use dd-wrt as my home router setup and that's been working fine. Now I wanted to figure out a way to be able to use my iPad to set up a IPSec tunnel to my home network while I'm on the road. PPTP ...
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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: ----------------------------- | | | ...
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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 ...
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Why is this iptables rule that does port forwarding not working?

I have a server bound to localhost:7060. It is using ipv6 socket instead of ipv4. Below is netstat outout. # netstat -an Proto Recv-Q Send-Q Local Address Foreign Address State tcp ...
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Iptables redirect to localhost?

Suppose I have a network with a server routing all connections from inside the network to the Internet. How can I set up iptables so that instead of routing incoming connections to the Internet, it ...
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How to allow FORWARDing with firewalld on a Fedora 19 router

I've just installed Fedora 19 and I'm using firewalld instead of iptables, but I'm having difficulty interpretting the new terminology. I have 2 NICs. One is specificed ZONE="internal" and the other ...
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411 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!
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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 ...
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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 ...
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5k views

Using iptables to redirect ip address

I have the requirement on a Linux system where the Linux device is using RSYNC to sync data to another Linux machine. This is working fine at the moment, however I need to move one of the machines to ...
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255 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, ...
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2k 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.
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192 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 ...
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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 ...
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Help with iptables

I recently installed Oracle Linux 6 on a home server, and I've been having trouble with allowing ports past the firewall (iptables). I've tried adding ports with the command iptables -I INPUT -p tcp ...
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1k views

How to transparently tunnel a port from IPv4 to a remote IPv6 device?

At home, I am connected with an IPv6 address and additionally, my provider provides a NAT-like setup through which I receive a public IPv4 address that I share with other customers (the reason being ...
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what does “-m tcp” mean in this iptables rule?

Firewall configuration written by system-config-firewall -A INPUT -m state --state NEW -m tcp -p tcp --dport 80 -j ACCEPT
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1answer
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Nginx works on my linux machine but is not accessible from other computers in my local network

In my LAN network I have a server with Scientific Linux (RedHat or Fedora based distro), I've done yum install nginx but the welcome page is not accessible from other computers in my network. When I ...
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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 ...
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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 ...
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843 views

Iptables port mapping from two PCs to one

We have 3 PCs, two of it are connected to internet (both of it have 2 NIC) PC1: eth0 - 1.0.0.1 (external IP) eth1 - 172.16.0.1 (internal IP) PC2: eth0 - 1.0.0.2 (external IP) eth1 - 172.16.0.2 ...
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DD-WRT Setting Up Guest Network

I have a router on which I installed DD-WRT firmware. I am trying to set up a virtual interface to use as a guest network. The guest network should be on the 192.168.8.0/24 subnet while our LAN is ...
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iptables equivalent in windows-xp,win7?

I want to do port forwarding in win7,what's the iptables equivalent in win7?
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What do these numbers mean in the output of iptable-save?

In the output of iptables-save # Generated by iptables-save v1.3.8 on Sun Mar 14 19:42:45 2010 *filter :INPUT ACCEPT [328764:37367248] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [324693:28884726] COMMIT # ...
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Logging communication between two VMs

I'm trying to set up "malware lab" described in this paper. So far, I've set up Windows guest system, adding one Host-only Network adapter, and setting this (sorry if the names aren't exactely ...
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Does tcpdump bypass iptables?

I mistakenly setup open resolver DNS server, which was soon used for bunch of DDoS attacks originating somewhere from / to russia. For that reason I completely blocked port 53 on both DNS servers for ...
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61 views

Cannot retrieve http sites when using OpenVPN, but https sites work just fine. Why?

I am using a VPN provider that uses OpenVPN. I don´t wont any other traffic leave my computer so I have set up my iptables like this: iptables -P INPUT DROP iptables -P FORWARD DROP iptables -P ...
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Combination of NAT, DHCP, and OpenVPN on lubuntu 14.04

Okay, so I've got a set up, where eth0 my internal IP address (192.168.1.3) it has been configured as my default gateway using the iptables this sudo sysctl -w net.ipv4.ip_forward=1 sudo ...
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700 views

Connecting to an SSH server behind a NAT

I am having trouble connecting to an SSH server behind a NAT on an ubuntu workstation. I've installed openssh package(both the client and the server) and forwarded port 22 through the NAT and tried to ...
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1k views

Bandwidth limit by Port on iptables

What iptables function would I use to bandwidth-limit all traffic on port 566 to 2KB/s? I'm confused about exactly how to do this.
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How to send out some traffic via my vpn connection

I had a working setup where I could access all my work resources which are accessed via VPN going via my server previously however at some point recently this stopped working for no obvious reason. ...
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What is command to look list of redirect rules, iptables

im using command like this : iptables -t nat -A PREROUTING -p tcp -d 192.168.1.118 --dport 4080 -j DNAT --to-destination 192.168.1.118:4088 My question what is command to look all rules in the ...
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OSX: Mimic Ubuntu IP Masquerading via iptables with ipfw

Good day, I am attempting to replicate a setup I have between a router and an Ubuntu PC, and have the same setup working on my MacBook (10.6, Snow Leopard). First, I have a router that has a USB ...
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1answer
439 views

Different routing rules for a particular user using firewall mark and ip rule

Running Ubuntu 12.10 on amd64. I'm trying to set up different routing rules for a particular user. I understand that the right way to do this is to create a firewall rule that marks the packets for ...
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How to block access to a website on Lucid Lynx?

I am trying to block a few websites on a lucid lynx, I tried editing /etc/hosts and that blocks access via url but the site still open if I enter the ip on the browser, how can I block ip access also? ...
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What Iptables rules need I to forward a windows remote desktop connection?

I have this situation: network mask. 255.255.255.0 router/gateway: Ubuntu server (only command line, no gui) with internal lan ip 192.168.0.2 and a dynamic dns on the external ip Windows pc on ...
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Program to block an IP temporarily with iptables

Is there a program on Debian to block an IP address temporarily just by launching a command (specifying the IP and the duration)? With iptables/ip6tables alone I can create a rule, but I would then ...
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154 views

vpn, IP forwarding and nat

I have setup a Softether VPN on an Ubuntu 14.04 server in an aws network which has about a dozen servers using this guide. The only difference is that I have used SecureNat and softether DHCP. I can ...
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1answer
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Linux iptables DNAT on incoming packet without conntrack (stateless)

In my linux box 10.20.1.1, i got two UDP apps binded on port 46000 (App A) and 36000(App B) respectively. The apps communicate with two UDP servers bindeded as 10.10.1.1:36000 (Srv X) and ...
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1answer
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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 ...
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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 ...
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When writing an iptables save file by hand, how does one calculate the packet-counter and byte-counter values?

I am attempting to write a 22MB iptables rule-set file, the very kind that is generated with the iptables-save command, except endlessly long. Understandably, this takes a prohibitive amount of time. ...
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176 views

Traffic not being forwarded through NAT

I have a router which provides internet access using NAT, and a client Linux box (A) which is connected to this router on eth0. This Linux box also has a wlan interface, wlan0; what I would like is ...
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How to route specific traffic through OpenVPN?

I'm running a server at home with rtorrent and apache2. I would like to route my rtorrent traffic via OpenVPN and since im kinda new to OpenVPN and iptables i would like to have a user friendly guide. ...
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1answer
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how to open ports for localhost on linux?

I've been reading for the past hour about opening ports on Ubuntu 12.04 and I can't seem to get anything to work. I'm running a program with an RPC server accepting local connections on localhost ...
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1answer
4k views

How to use NAT iptables rules for hostapd

My PC is equipped with two net interfaces - wlan0 and eth0. I want to use WiFi port as access point on wlan0. So i use hostapd facility and it works properly in routing mode in local network. Users ...