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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IPTables and PPTPd

I'm trying to add the line -A POSTROUTING -i ppp0 -j MASQUERADE to my IPTables in order to allow VPN to have access to the entire internal and external network (eth0, and eth1), but when I try to ...
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I want to exclude the port xxxx from my iptable rule

I want Transmission to use the vpn (tun0) for the torrent stuff, but I also want to access the web interface from my local network. Any suggestions? For the first part, I already tried this.
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153 views

iptables --append FORWARD required for routing between NIC alias IPs?

I have an ubuntu box with a single NIC. In order to bind a number of services (like apache, dnsmasq, etc), I have bound them to different alias's (e.g. eth0:0, etc), some of which are on completely ...
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105 views

How to add iptable support to the kernel (for Wheezy/Sid release)

I am running an ARM processor (similar to the raspberry pi) and my kernel doesnt natively support iptables. If I run apt-get install iptables, it successfully installs but NAT tables are unable to be ...
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553 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 ...
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linux machine as two internet gateway connection?

I have linux machine (arch linux) which has there network interface eth0,eth1,eth2 AND two vlan eth0.1 192.168.10.1, eth0.2 192.168.20.1 and two Internet connections eth1 10.0.0.1, eth2 10.0.0.2 how ...
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26 views

Firewall rule for local, interactive users?

I want to add a firewall rule that applies to a local interactive user. The intention is to clamp down the box, and only allow web and mail related connections, and update service connections. On ...
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47 views

Run shell script on incoming network package

I have a bit of a weird question. I have a setup where a Raspberry Pi (running that debian) sits next to a door in my office and is connected to the network. The idea now is that if somebody inside ...
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How should I configure my Tor-dedicated firewall for optimum security?

I'm setting up a Tor-based isolating proxy using the 'Anonymizing Middlebox' iptables rules specified here: https://trac.torproject.org/projects/tor/wiki/doc/TransparentProxy i.e. iptables -t nat -A ...
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151 views

How do I fix these iptables?

I am trying to setup my networks firewall, and am having trouble because i keep getting kicked out of SSH because of mistakes. Here's what I currently have: # Custom Rules iptables -F iptables -X ...
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Using telnet to router (iptable), set up squid proxy for specific websites and/or from sepcific host

I have a router to which I can telnet. I checked and it allows me to tweak iptable as well. I have a remote VPN running Squid3 which is tested and works fine. Now I want to tell my router by iptable ...
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Mirror Port via iptables

I have a dedicated Linux (Debian 7.5) root server, with a number of guests set up. The guests are KVM instances, and get network access via bridge-utils (NAT, internal IPs, use the host as a gateway). ...
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114 views

Why is change to iptables not taking effect?

Im trying to setup OpenVPN to use Tor as a proxy in Liberte. When I run openvpn as root, I get the following response: Tue May 13 15:15:18 2014 Attempting to establish TCP connection with ...
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46 views

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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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: ...
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Why are these iptable rules keeping me from browsing the internet? (allowing 80,443,53)

This is for my home machine. Here are the rules: Chain INPUT (policy ACCEPT 0 packets, 0 bytes) num pkts bytes target prot opt in out source destination 1 ...
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iptables: Allowing multicast & other traffic on LAN, not to WAN

I have a Linux 3.10 machine functioning as a NAT router between the wlan0 LAN and the eth0 WAN. I would like to allow all communication between machines on the LAN (they are trustworthy) and allow ...
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118 views

Fedora / Vagrant Firewall Issue: Unable to Connect to HTTPd / MySQLd / Webmin

Yesterday, I migrated from Ubuntu to Fedora 20, and after some fiddling with NFS and iptables I was able to get my vagrant instance (CentOS 6.5) to boot, mount the NFS share, and was able to access ...
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iptables eth0 wlan0 bridge not working

I am trying to allow an embedded system to share the wireless of my laptop. The embedded system is an A20 Olinuxino Micro running Debian and my Laptop has Ubuntu 12.04. I tried this which has worked ...
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29 views

Transparently proxifying certain devices on the network

I'm using my computer as wireless access point and router to my home network using hostapd under Ubuntu 14.04. I want to transparently proxify certain wifi devices in the network (identified by their ...
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104 views

How to share ppp0 to wlan0 with redsocks

I can't understand the meaning of this: I have a USB modem along with a USB Wifi router, and I use redsocks for ppp0. Then I want to forward the incoming connection from Wifi to redsocks. I have ...
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Packets From Inside Not Being Forwared To Outside

I'm trying to forward internal packets to outside without success. iptables -t nat -A PREROUTING -i eth0 -p icmp -d "internal IP" -j DNAT --to-destination "external IP" iptables -t nat -A PREROUTING ...
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Iptables on mini-Linux, hosting VMware Player with Windows, blocking access to www

we have a special kind of system at the university. A mini-Linux (Ubuntu 13.x) is loaded via PXE, afterwards the VMWare Player on this Linux is starting a selected VM. The connection setting of the ...
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48 views

Ports in Linux vs Windows

I'm studying for a security class. I know that ports in Linux are tied to a process. So if I wanted to close/shutdown a port, I'd end the process that's using it. So if I'm in Windows, what's ...
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How to check/adjust SSH server on embedded board

I'm currently having difficulties connecting to an embedded board from my Linux machine through ssh. The embedded board is a FOX G20 V with a Linux OS. I've tried to connect to the board through ...
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135 views

Redirecting internal traffic to gateway's port-forwarded external endpoints directly to intranet destination

There's an intranet and CentOS-powered gateway that provides connectivity for intranet devices. Typical port-forwarding in gateway's iptables ruleset looks like this (TCP version is provided): ...
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89 views

Granular routing with iptables and iproute2 over VPN

On a host at my house I have a host for a VPN that I need for a couple of purposes. Living temporarily in Japan, it functions as a NAT for some devices so I can still use my NETFLIX and some other ...
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679 views

iptables blocking all traffic even with ports opened

Simple as I can put it: I can't access my servers with iptables enabled, with default rules. Need to disable iptables to get access. Trying to find the cause. Only difference in setup type is layer3 ...
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120 views

Can't connect to web server from outside my network

I have a Debian-based server that I would like to be able to access from the Internet (no domain name yet, I'm just trying to get it working for now). I already have port forwarding set up on my ...
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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: ...
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Conntrack/NAT's port mapping for a specific port breaks whenever that port's service is shutdown for too long. How can I fix this?

Linux Gentoo 3.13.6-hardened-r3 #1 SMP Sat Apr 12 09:17:25 EDT 2014 x86_64 Intel(R) Core(TM)2 CPU 6300 @ 1.86GHz GenuineIntel GNU/Linux hardened with grsecurity and selinux with a strict policy in ...
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64 views

How to specify a certain device to access the Internet via the OpenVPN client of router?

Involved Devices: a VPS, a router, and several devices that connected to the router. Final Aim: Base on the OpenVPN client which has connected to the server on the VPS, specify only one local device ...
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166 views

Iptables deny access to a specific IP address not working

I'm not able to deny access to a specific IP address or deny access to a specific IP address range as well. My network environment is, I have one router which IP is (30.30.10.1) and second my hotspot ...
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760 views

Route internet traffic from openvpn tun0 to eth0

I can't figure it out. How do I give chosen VPN-users access to internet trough eth0? All server traffic goes trough eth1. The eth0 is only supposed to give VPN-users internet access on chosen ports ...
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509 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 ...
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491 views

configure iptables to block all(as much as possible) bittorrent traffic

good day all This is my current iptables setup Generated by iptables-save v1.4.7 on Wed Apr 9 13:50:31 2014 *filter :INPUT DROP [0:0] :FORWARD DROP [0:0] :OUTPUT ACCEPT [0:0] :LOGDROP - ...
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Segregating/Separating a device (ATT 3G Microcell) from internal network without using DMZ

I would like to put the ATT 3G Microcell in an isolated network from a network that has the rest of my devices, by which I mean I want the ATT 3G Microcell to only be able to access the Internet, but ...
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126 views

IPtables preventing outgoing packets

I am trying to setup firewall rules on a RHEL webserver, so that my webserver can serve up web pages and at the same time download remote files using curl/wget. Problem I am experiencing is I can only ...
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86 views

Display port numbers and port names

How do I display both port numbers and port names at the same time? I can display the forward port numbers (i.e. 22, 25, 1000, 443, 80) using the following: [root@michaels ~]# iptables -L -n Chain ...
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569 views

Routing internal traffic in centos to the internet using iptables

Hello friends i am struck in routing traffic from the office to internet i have a network structure like this http://asthana.me/images/ip.png I have assigned static ip to the cent os server(which ...
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152 views

Bind incoming packets to 1 interface and outgoing packets to 2nd interface?

I am have a Linux machine with 2 network interface cards, I need to use one for incoming packets, other for outgoing packets.
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58 views

Turning iptables off on development server permanently?

What would be the downsides of turning off iptables permanently on a development environment? I don't like the fact that every time I restart virtual box I must do: service iptables stop service ...
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How to allow squid to grant access for outlook

I have configured squid at RedHat Linux 5.4 and all my Windows networks use 192.168.5.100 and port 3128 as proxy for accessing Internet. But while sending and receiving emails at Microsoft outlook ...
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How to forward ports through ssh and nat to another machine

I have a problem when using ssh port forwarding and nat simoultaneously. Situation: Machine A runs a webserver on port 8080 Machine B is a raspberry pi which works like a little router. It has two ...
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453 views

Chromecast and accessing Netflix from outside the US

I have given this as an answer, but there is a question involved so that's why I'll post this again. You can find the answer here: http://superuser.com/a/734838/311358 I have a computer (iMac) that ...
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88 views

Connected to vpn but can't connect to internet

I am using ubuntu 12.10 as a vps. And I am trying to configure a vps server on it. I can connect to the vpn but just can't get internet access. Maybe because I don't know how to write a iptables. ...
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Blocking an outbound port for a bridge'd nat'd inteface

eth0 and wlan0 are bridged to br0, and have access to the outside world through eth1 and NAT. I'd like to block an outbound port on wlan0, but leave it open for eth0.
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packages from router dont match iptables dnat rule

I have the follow rules to forward port 443 from external to a internal host: IF_INET=ppp0 IF_INET_IP=1.2.3.4 # Router External IP IF_LAN_IP=192.168.0.1 # Router Internal IP ...
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How to stream WiFi cameras over a Linux gateway to my laptop using iptables?

My setup is as follows: Linux gateway has one WLAN configured as WiFi client (192.168.0.100) to a Linksys WiFi AP(192.168.0.1). There are three WiFi cameras connected as WiFi clients (192.168.0.101, ...
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Can't SSH into a computer that is connected to a VPN

I set up a linux machine with an ssh server that I can connect to from an external network. When I have the server computer use a private VPN though, I can't ssh into it remotely anymore. Is there ...