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

0
votes
1answer
850 views

iptables + vpnc + Cisco IP Phone 7941

I have a Linux gateway with kernel 2.6.39 connected to a Cisco ASA 5500 with vpnc. I'm using iptables with masquerading and forwarding to give the LAN access to the tun0 device connected to the VPN. ...
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 ...
1
vote
0answers
112 views

How can I restrict my Virtual Machine using an iptables rule?

I am using CentOS Linux and am planning to setup a rule on my VM's iptable. I want to restrict all outgoing and incoming packets to the VM for a temporary period and allow only the DHCP packet to ...
1
vote
1answer
4k views

How do I block all ports except 22 and 80 in Fedora's iptables? [duplicate]

I am trying to only allow port 22 TCP/UDP and port 80 TCP/UDP from anywhere using Fedora 15 iptables, and all the rest will be never accessible nor scannable from a public network. But it never ...
0
votes
2answers
147 views

iptables ACCEPT policy

In Redhat EL 6, iptables INPUT policy is ACCEPT but INPUT chain has REJECT entry in the end. /etc/syconfig/iptables is as below: *filter :INPUT ACCEPT [0:0] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [0:0] ...
2
votes
1answer
5k views

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 ...
0
votes
2answers
503 views

Blocking a botting URL to an Linux server running Apache

I have a webserver running OpenSUSE 11.1 and I need to block a URL. The reason I want to block a URL is because it seems to have a different IP address all the time, but the URL stays the same. I'd ...
1
vote
3answers
794 views

I need a traffic monitor for Linux, that only counts in a specific wireless network

I need a simple traffic monitor for Linux, that counts the traffic in a specific wireless network because I have volume restrictions on that one. I tried it using the following iptables rule: ...
2
votes
1answer
919 views

How do you add a MAC-based routing whitelist with DD-WRT and the OpenVPN client?

I have an OpenVPN client set up on my DD-WRT home router which maintains a VPN into my workplace. Slight problem: I don't want random lusers who access my wireless AP to have access to my company's ...
1
vote
1answer
591 views

Fedora 14 system-config-firewall-tui gone?

On Fedora I used to be abble to configure custom ports into the Firewall by going to setup and following the required steps till I got to something like this: Well that menu is here no more. I can ...
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 ...
4
votes
2answers
5k views

Ubuntu 11.04 server iptables port forwarding

I'm pretty new to iptables. My server has two Ethernet cards (eth0, eth1) and an ADSL router that is in bridge mode connected to the eth0 which created ppp0 when dialed. I'm trying to forward ...
5
votes
1answer
548 views

Rackspace Firewall/Gateway Setup

I have rackspace account and wish to have this sort of setup: Firewall/Gateway eth0 - Public IP (56.X.X.X) eth1 - Private IP (10.X.X.X) Ubuntu 10.10. Accepts connections from the internet and ...
0
votes
1answer
3k views

iptables openvpn forward selectively from eth to tun

Simple for those who know, indecipherable for those who don't... I'm running openVPN on (hypothetical) 66.66.66.66, I want to FORWARD incoming traffic, arriving on interface eth0 to interface tun0. ...
0
votes
1answer
2k views

How do I get an iptables redirect to survive a reboot on SuSE 11?

I've set up iptables to forward from port 80 to port 8090: iptables -t nat -I PREROUTING -p tcp --dport 80 -j REDIRECT --to-port 8090 However the redirect is gone after rebooting. What's the ...
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 ...
1
vote
0answers
256 views

Can ipmasq and ufw be used together?

If both ufw and ipmasq manipulate iptables, can I use ipmasq for a quick easy setup and then use ufw afterwards to add security or will the two just trample all over the iptables "stuff"? I'm playing ...
1
vote
1answer
535 views

iptables drop fake ip packets

I'm trying to drop all packets from the internet that use a fake ip address so they appear to come locally. Do I need both lines or only the first ? --append INPUT ! --in-interface lo --source 127....
1
vote
2answers
415 views

iptables rules revert on Ubuntu

I'm using iptables on Ubuntu 10.04 and whenever I set iptables rules they will revert after a while. I set them with iptables -I INPUT or iptables -D INPUT and they work immediately and I see them in ...
6
votes
1answer
6k views

Disable or block outgoing email

To do web site testing, how can I disable or block the Centos server to not send out emails. Now, if I run in command line mail xxx@gmail.com I can send out emails. This is not good for website ...
1
vote
3answers
3k views

iptables restrict ssh session by mac address

I'm in the process of restricting access to my Linux production box, where ssh access needs to be limited to only a few MAC addresses. I've followed the instructions outlined in this guide and ran ...
1
vote
2answers
5k views

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 ...
0
votes
1answer
917 views

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 ...
1
vote
2answers
428 views

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. ...
0
votes
2answers
795 views

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 ...
0
votes
1answer
638 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 # ...
2
votes
1answer
2k views

iptables equivalent in windows-xp,win7?

I want to do port forwarding in win7,what's the iptables equivalent in win7?
2
votes
1answer
617 views

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 ...
4
votes
3answers
8k views

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 ...
1
vote
1answer
759 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 ...
0
votes
1answer
465 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 ...
1
vote
2answers
2k views

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.
0
votes
1answer
1k 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 ...
1
vote
1answer
1k 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 ...
0
votes
1answer
423 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 ...
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 ...
0
votes
1answer
750 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 ...
1
vote
2answers
448 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 ...
5
votes
1answer
7k views

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
0
votes
1answer
655 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 ...
0
votes
1answer
638 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, /etc/rc.d/...
1
vote
1answer
2k views

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 ...
2
votes
2answers
1k 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 ...
2
votes
0answers
549 views

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 ...
0
votes
1answer
682 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 ...
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 ...
0
votes
1answer
93 views

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. ...
0
votes
1answer
490 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 access....
0
votes
1answer
155 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 ...
0
votes
0answers
251 views

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 ...