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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Setting up a Linux server with a public Static IP

I have setup a Ubuntu Linux server in an office. It should have a public IP so that outside users can access the internet. Currently, it is set with a public IP, but is it supposed to have a local ...
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Iptables prerouting and IP forwarding

I have a linux machine used as gateway for a Win XP machine. Both are in Virtual machine for testing purpose. Now I want to trick the Win XP user (me) with the forwarding of an IP address: I want to ...
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Is this firewall completely secure?

I'd like to know if there's any holes/flaws in this firewall setup. I want to lock down the server as much as possible so it is impossible to hack in to. The only services running are openvpn and ssh. ...
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How evade firewall port blocking?

I have a serious problem with my institute's firewall. I have a Rackspace Cloud server instance that is configured to accept SSH connections on port 6xxx. When I was using port 22 there wasn't any ...
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563 views

Removing/Disabling Firewall on Linux CentOs seem to happen temporarily

I tried following the instructions in this link to disable and remove iptables firewall using commands: # service iptables save # service iptables stop # chkconfig iptables off # iptables -F # ...
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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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Save iptables when iptables-save doesn't exist?

I'm working on a Soekris net4801 that is running an unknown distro of Linux. The kernel is 2.4.29, and iptables is v1.3.4. I can't work out how to save the iptables. I searched the whole system for ...
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iptables for transparent TCP proxy

Here's my situation. I have an iPad, a TiVo, and an dd-wrt router on my network, along with a machine that I'd like to use to sniff/decrypt draffic between the iPad and the TiVo. The iPad has an app ...
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657 views

Feedback to router users during access-restricted hours for DD-WRT

Following router schedule rules that I change often, the stock firmware on my D-Link 825NA rev. B redirects HTTP requests to a built-in "Access denied!" warning at appointed times. I just upgraded ...
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440 views

Firewalling all incoming traffic with custom rules

How do you automatically block all incoming traffic by creating custom rule for every connection (in real time) using iptables? To clarify - the situation is that my linux box is being DDOSed via ...
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Howto compile a kernel module on CentOS [required packages]

What yum commands do I need to get available packages installed on CentOS to build a iptables MATCH kernel module.
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838 views

Internal working of rules in forward chain for NAT

I am trying to understand how exactly NAT works to solve another bigger problem, here is my linux box setup: Interface eth0 connected to internet (public IP address) eth1 connected to local network ...
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983 views

loopback error, home network

I've setup my router to forward port 80 through to my computer, so I can access it from a dyndns.org domain. The domain and the ip both seem to be totally working, externally (can access it from ...
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386 views

Linux box acting as wireless access point to share the internet connection

A linux machine is connected to internet over two interfaces ppp0 and ppp1 using two modems. Also this machine acts as wireless access point through an interface say, eth0 with ip address 192.168.1.1 ...
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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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565 views

Quotas with iptables

pkts bytes target prot opt in out source destination 12770 2385K ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 quota: 2000000 bytes 0 ...
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435 views

iptables - router configuration

I have a router that I am customizing settings for. I want to only allow SSH from the internal network and drop everything else. This is what I have so far. I tried it and I had to reset my router ...
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tc / iproute2, how to list the configuration

This is my first time using traffic shaping and I am wondering how I can list the rules I applied like you can with iptables? Walter
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568 views

iptables firewall rules not allowing ssh from lan to DMZ

Chain INPUT (policy ACCEPT) target prot opt source destination REJECT tcp -- anywhere anywhere tcp dpt:www reject-with tcp-reset REJECT tcp ...
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478 views

IP Tables won't save the rule

I'm using ArchLinux and I have an IP tables rule that I know works (from my other server), and it's in /etc/iptables/iptables.rules, it's the only rule set in that directory. I run, ...
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DD-WRT OpenVPN client - cannot get “lan” connected device to route traffic

I have OpenVPN client setup on DD-WRT openvpn small. client connects and can use traceroute to verify everything is tunneling out the openvpn connection. ip_forward is 1. iptables -t nat -A ...
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2answers
955 views

Using iptables to selectively route outgoing requests?

I'd like to set up my Dd-WRT firewall so that it uses the VPN service from a VPN provider to access a bunch of destinations and normal route foe all other requests. In detail: giganews.com would be ...
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Why does my Tomato router seem to behave badly as time passes

I've set up a Firewall script on my Tomato router (a WRT54G 2.0, actually) that seems to behave correctly at start, but after one or two days, it seems that the script does not work anymore... The ...
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656 views

Ubuntu 9.04, Firestarter complaints even behind the NAT router

I'm behind a router. In router config, I blocked: all (inbound and outbound) UDP inbound ICMP Local iptables are configures with Firestarter wizard: block all incoming connections allow all ...
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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 ...
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Network problems that might be related to NAT

I have an odd setup where there is a router(Router 2) routing between network network 1 and network 2. One router(Router 1) with nat for internet access that routes between internet and network 1. ...
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408 views

Create iptables rules

I want to make the following rules in iptables: Open port 80, 5432 and 22 to all IP addresses Open port 27017 only to these IP addresses x.x.x.0/24 In all the cases I want both tcp and udp ...
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148 views

no websites loading using iptables nat

I'm using a 3G modem whilst o2 tranfer over adsl. trouble is no websites load but I can resolve domains. I enabled masquerade on the PPP0 ( modem) interface. added the server as default route for all ...
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Fedora iptables error

I recently installed Fedora 13 and receive this Boot message: iptables: Applying firewall rules: iptables-restore: line 14 failed I am new to Linux and need help in figuring out how to fix ...
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856 views

iptables and NetworkManager on Ubuntu

I want to use iptables configuration on my Ubuntu 10.0.4 desktop, however I read that Network Manager and iptables have some conflicts. Should I uninstall NetworkManager? If yes, how? ...
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How to install firewall script in Ubuntu?

https://help.ubuntu.com/community/Router/Firewall In the link above there is a firewall script described. How can I install this script in Ubuntu 10.0.4 desktop?
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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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iptables LOG actio writes to STDOUT

when I use LOG action in some chane of iptables rules, I get the output both in STDOUT or STDERR of the xm console and in /var/log/messages. Is there way to make iptables to write only to log ...
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how do i set up this firewall?

i use fedora 13, and i have firewall turned off now. but i want to allow all incoming connections and outgoing connections except to a port P. i want to allow connection to port P only from certain ...
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How to deliberately introduce a delay for incoming UDP packets

I want each packet (that match iptables rule) to be delayed by some fixed time interval. How to to this? Preudocode: iptables -A INPUT -p udp <more conditions> -j DELAY --delay 50000 # delay ...
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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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290 views

how do I forward *only* http proxy across vlans?

My router has two bridges, br0 and br1. I'm sharing wifi access, and the guest subnet will be 192.168.2.x. The home subnet will be 192.168.1.x. I want all traffic destined for port 80 from the ...
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Block all ports except SSH/HTTP in ipchains and iptables

How can I block all ports except ssh (port 22) httpd (port 80) using iptables and iphains?
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Block all but http traffic on a network interface

I've got two network interfaces on an Ubuntu machine which go out to two different networks but both have internet gateways. I need to limit it so that any outgoing http requests it makes (ie ...
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156 views

How to setting up iptables for traffic fowarding on port 80 from specific sources

Im running a web server on port80, but i want traffic coming from ip 212.333.111.222 on port 80 to be fowarded to port 9020 on the same server that my web server is rinning at that is my sshd port
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iptables: separate clients from each other

is there a way to separate clients in a subnet so that they cannot reach each other? The infrastructure currently looks like this: 192.168.0.1/24 Gateway, a CentOS box with iptables. ...
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What are the iptables rules to permit ntp?

My server's clock is wrong because the firewall doesn't permit ntp traffic. What are the iptables rules required to allow the ntp client to get out and back? Any suggestions how to implement those ...
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Routing from the DMZ to the interior network only

I have a home network connected to Verizon's FIOS service. Verizon's ActionTec router is connected to the ONT via coax to establish the MOCA network. My DD-WRT router's WAN port is connected to one ...
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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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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? ...
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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 ...
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One website not connecting over shared connection

A website is not opening on a computer that's connected via shared connection (not exactly "shared"). Pinging the website gets Packet filtered message. The setup of my home network is done by Ubuntu ...
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Blocking access to a specific url

I have a lightweight linux device which I would like to block from accessing one specific URL. Instead of making the request to the external URL, I would like to return the contents of a local file. ...
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How to use FQDN in firewall rules for GNU/Linux?

I'm trying to setup a firewall for one of GNU/Linux systems. AFAIK, iptables and its ilk cannot make use of FQDNs in their configuration, since they're expected to be operational before the network ...
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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 ...