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
653 views

Port 6667 can't be reached outside of localhost

I've got IRCD-Hybrid installed with the following listen config: /* listen {}: contain information about the ports ircd listens on (OLD P:) */ listen { /* port: the specific port to listen ...
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 ...
6
votes
2answers
289 views

Open up firewall automatically to anybody who has successfully connected via SSH

I have a server which runs a few services. However, for security reasons, I configured the server so that nothing, except for SSH, is accessible from outside. What I'd like to do instead, though, is ...
6
votes
1answer
6k views

How to configure a firewall on Centos using Vagrant and Chef

I've created a server box using Vagrant and Chef and everything is up and running correctly. However, when the box is installed from scratch the default iptables rules are in place and so I need to ...
1
vote
1answer
1k views

Filter multicast from WAN to specified vlan

I'm using ebtables to filter multicast IPTV from my Wireless and Wired Lan. Right now its configured like this: Router ( DD WRT ) VLAN1 (PC Network) VLAN2 (IPTV) I am using this command: insmod ...
1
vote
0answers
815 views

tc/netem and iptables: Delay traffic only from specified ip and port

I have a Ubuntu Router with 2 network interfaces. eth0 is the private network and eth1 is the internet. What I want is the following: All packages (mostly udp) comming from a specified private ip ...
2
votes
2answers
3k views

How to redirect a port using IPTables in Red Hat Linux (RHEL)?

I'd like to forward port 80 to 8080. So I tried to edit /etc/syscongfig/iptables: -A PREROUTING -t nat -i eth0 -p tcp --dport 80 -j REDIRECT --to-port 8080 But got: # service iptables restart ...
1
vote
1answer
1k views

iptables routing marked packets from router to PC and routing them back to router

I'm trying to do deep packet inspection on HTTP packets. The purpose of this is to collect HTTP payload data and then create some proxy/cache-independent reports. Following this, the idea is to ...
1
vote
0answers
182 views

How to unblock jabber on TI ADSL router with iptables

I have old but reliable Texas Instruments ADSL router. Board AR7RD; BUILD=061005; VERSION=3.7.1 If that matters... One thing that bothers me is that it somehow blocking my jabber (Pidgin ...
2
votes
1answer
956 views

IPTables - unknown error 4294967295

I've moved an old Slackware 11 installation from a physical PC to a virtualized in ESXi. Everything seems to work fine except for one rule in iptables, namely the row: iptables -t filter -I INPUT -m ...
4
votes
1answer
2k views

Access Apache server running in Fedora guest VirtualBox from host

I have trouble accessing Apache server from host. I’ve Fedora 15 VM VirtualBox installed on Windows 7. Within this VM I have Apache server running and working fine within the guest. Not sure what ...
2
votes
1answer
235 views

amule, Fedora 14, iptables

I need to set iptables rules for aMule, but I am not sure which one are the right ones. Googling around, I have seen something like: iptables -I INPUT -p tcp --dport 4662 -j ACCEPT iptables -I ...
1
vote
2answers
1k views

How to “shut off” all networking on Linux from bash?

I'd like to write a bash/shell script that "turns off" the machine's ability to communicate over it's network card, effectively shutting down all networking. From the command line: # To turn all ...
0
votes
1answer
807 views

how to telnet redirect ip and host using iptables

I try to telnet from PC 3 To PC 1 and it's redirect to PC 2 PC 1 : 192.168.0.1 PC 2 : 192.168.0.2 PC 3 : 192.168.0.3 i have command like this in PC 1: iptables -t nat -A PREROUTING -p tcp -d ...
4
votes
1answer
3k views

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 ...
2
votes
1answer
1k views

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. ...
1
vote
2answers
2k views

iptables port based routing

I've been Googling this for days with no success. I connect to a VPN from my server from time to time and I'm trying to configure my Debian server to only use port 80 and 443 through the VPN and all ...
1
vote
1answer
115 views

why does this iptable rule work at a specific position in the chain

I'm running OpenWrt on my router, which allows me to run applications such as apache and emule. I installed emule but I keep getting lowid, indicating that my port is misconfigured. I was able to ...
1
vote
0answers
142 views

No output returned when curl ing any URL in Red Hat 6 but the same url works in lynx browser

I am trying to install some packages in Python using easy install. But i get a 'Download Error' for any package i try to install. So i tried to test if internet is accessible at all from the machine ...
2
votes
2answers
5k views

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. ...
2
votes
2answers
2k views

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 ...
0
votes
1answer
435 views

How to resolve conflict in iptable rules

In Ubuntu 12.04 and above there are no iptable rules defined by default. I added the following rule and it works fine:(Update) iptables -A INPUT -p tcp -j QUEUE -m string --string xyz --algo bm ...
0
votes
0answers
220 views

1:1 NAT IP address using iptables

Suppose I have 2 internal networks: 1.1.1.0/24 and 1.1.2.0/24 I would like to NAT a specific IP address from one network to the other, in which the new address would be obtained via DHCP. For ...
0
votes
1answer
722 views

MIxing RFC1918 NATed and public IP addresses using IPTABLES

I wish to host a SIP server and DNS at the end of an ADSL2 connection. My current network sits behind an iptables firewall which runs on a Linux box with two Ethernet interfaces, the WAN interface ...
0
votes
1answer
116 views

IPTables Allowing Access without Rules

I'm sure this is mostly my misunderstanding of how iptables works, but I've set up some rules... -A INPUT -p tcp --dport 22 -m state --state NEW,ESTABLISHED -j ACCEPT -A OUTPUT -p tcp --sport 22 -m ...
5
votes
1answer
2k views

How to configure port forwarding for an IP camera

I need to configure port forwarding for my IP camera so that I can access it from internet. UPNP is not supported on my gateway. My network configuration is the following: Gateway (Ubuntu Server 12) ...
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 ...
4
votes
1answer
4k views

Load balancing with multiple gateways

I have to different ISPs, each on each own network. The main connects via ethernet and the secondary via wifi. The two networks have no relation at all. I just connect to them simultaneously. The ...
1
vote
2answers
9k views

need to route the traffic through a specific network card

I have two network cards and they both have a different network. I need the outgoing connections to go only through a specific network card. Any help ? Update: I ran a route -n command and got this ...
2
votes
1answer
308 views

Why does Firefox need a loopback connection?

I was playing around with firewalls and iptables. When I blocked any traffic except HTTP and DNS I was able to establish a connection to google.com via wget google.com. But I wasn't able to open ...
1
vote
2answers
923 views

iptables block everything except http

I'm trying to configure my iptables to block any network traffic except HTTP: iptables -P INPUT DROP #set policy of INPUT to DROP iptables -P OUTPUT DROP #set policy of OUTPUT to DROP iptables -A ...
2
votes
0answers
351 views

Centos iptables blocks after reboot

I have a Centos5 installation with kvm on my server. I am using nat portforwarding to ssh my virtual machines. I have several iptables rules and saved then in /etc/sysconfig/iptables. After reboot, I ...
1
vote
0answers
332 views

IP forwarding with iptables

Suppose there are hosts A and B. A is allowed SSH access to B based on its IP address. Consider now another host C. C does not have access to B, but if we could route its traffic through A, then C ...
6
votes
2answers
18k views

CentOS 6 - iptables preventing web access via port 80

I'm setting up a new web server with CentOS 6.2 and am not able to connect via the web. Everything looks set up correctly in httpd.conf and Apache is running, so I'm assuming it's an iptables issue. ...
2
votes
1answer
289 views

dd-wrt: Keep source ip after port forward

I just started using dd-wrt on my wndr3700, but now all my incomming connections to a server inside the network gets the same source ip as the router. How can I change this back so I get the real ...
2
votes
1answer
611 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 ...
-2
votes
1answer
383 views

IP tables gateway

I am trying to make an iptables gateway. I ordered 3 dedicated server from my hosting company all with dual nics. One server has been given all the ip addresses and is connected directly to the ...
1
vote
1answer
1k views

Pinging an external server through OpenVPN tunnel doesn’t work

I have an OpenVPN server and a client, and I want to use this tunnel to access not only 10.0.8.0/24 but the whole internet. So far, pinging the server from the client through the tun0 interface works, ...
0
votes
1answer
303 views

CSF Unresolved issue

I began receiving service failures for CSF/LFD once the limit was reached in iptables preventing the service from working properly. I flushed all iptables rules, and redid by rules using CIDR rather ...
1
vote
0answers
580 views

iCloud stuff stops working while connected to OpenVPN

I have a fairly simple OpenVPN setup on an OpenVZ VPS with Ubuntu 11.10. Client is the Viscosity client on Mac OS X 10.8.2, and after some testing, we can rule out the client as being part of the ...
1
vote
0answers
322 views

Load-balancing: response packets not routed - iptables

I have a problem with iptables. I'm trying to setup a load balancer between 2 uplinks. I can mark packets and connections, use ip rule to choose routing table (so changing the gateway). But, when I ...
1
vote
2answers
762 views

Packets marked by iptables only sent to the correct routing table sometimes

I am trying to route packets generated by a specific user out over a VPN. I have this configuration: $ sudo iptables -S -t nat -P PREROUTING ACCEPT -P OUTPUT ACCEPT -P POSTROUTING ACCEPT -A ...
0
votes
1answer
70 views

Is there an alternative of TrivialProxy for linux?

Does anyone knows an alternative software of TrivialProxy for linux? iptables is not enough because I need a GUI. Thanks in advance.
1
vote
0answers
569 views

Routing table on Linux not respected

I have a very specific problem, building a Linux VPN endpoint (with external VPN Gateway), which should route certain networks over the tunnel, others via default gateway. The Linux VPN should do a ...
1
vote
1answer
444 views

Rate limiting traffic between specific hosts (based on their MAC) using iptables

I have setup a simple isolated network consist of following Linux based machines (simplified example): Node1<---->Router<---->Node2 Router's eth0 is connected with Node1's eth0. Router's eth1 is ...
1
vote
1answer
649 views

Reasons why ports below 1024 cannot be opened

I'm root on a machine I don't know how it was configured. I try to open SSHD on another port than 22 but it does not work. I changed the /etc/ssh/sshd_config file and added a new Port line extra to ...
1
vote
1answer
784 views

Difference default setting on iptables between CentOS 6.3 and Ubuntu 12.04

I would like to ask in ubuntu 12.04, there is no firewall settings by default? iptables -L Chain INPUT (policy ACCEPT) target prot opt source destination Chain FORWARD ...
1
vote
0answers
170 views

Is there a decent diagram of packet flow for a modern era (2.6+) iptables setup?

I'm currently trying to debug a particularly hairy set of DNAT based iptables rules (the UDP reply never makes it back to the original requester) and I'm struggling to visualise the packet flow ...
1
vote
1answer
78 views

iptables -L lags on non localhost or anywhere address

I am trying to configure iptables for ubuntu 10.04 and I have a problem with iptables -L lagging on rows where the destination or source address is not localhost or anywhere. The following entries ...
2
votes
1answer
5k views

Reverse Proxy for TCP (RDP, VPN, etc) and HTTP

I have a domain that points to my ISP assigned IP though a CNAME (cname goes to my noip address incase my ISP decides to change the IP), I would like to route different subdomains to various IP:PORT ...