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Questions tagged [iptables]

GENERAL IPTABLES SUPPORT IS OFF-TOPIC. Support questions may be asked on https://superuser.com. An application that allows administrators to configure the packet processing tables provided by the Linux kernel firewall. Use this tag only for questions on programming with iptables. Questions about configuring iptables should be asked on Server Fault (https://serverfault.com/tour).

An application that allows administrators to configure the packet processing tables provided by the Linux kernel firewall. Use this tag only for questions on programming with iptables. Questions about configuring iptables should be asked on Server Fault.

Links:
Linux Firewall Tutorial: IPTables Tables, Chains, Rules Fundamentals
Iptables Essentials: Common Firewall Rules and Commands

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How to forward source IPs to Docker containers without letting Docker mess with iptables

if you run something (e.g. nginx) in a Docker container and publish one of the exposed ports to the outside world (like docker run -p 80:80 nginx) then Docker will expose the port to the public set up iptables so that if something connects to the…
Mate Varga
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The -t option cannot be used in iptables-restore

I got this error when I want to restore my iptables rules from file. iptables-restore v1.4.21: The -t option (seen in line 5) cannot be used in iptables-restore. Error occurred at line: 5 Try `iptables-restore -h' or 'iptables-restore --help' for…
PumpkinSeed
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iptables --sport vs --dport. INPUT vs OUTPUT

I am having some trouble understanding iptables. I know it acts as a filter but something isn't clicking because it isn't working the way I think it should. Let me start by saying that I'm creating a white list, so all policies (INPUT, FORWARD,…
J.M.
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How do I use bash to bulk add a file full of IP blocks to IPTables

How can I bulk add a text file full of IP blocks to IPTables using BASH (or another scripting language)? Or is there some other way of blocking these address ranges? EDIT: In other words is there a way to program something to iterate through the…
Matthew Brown aka Lord Matt
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Iptables forward port range to another port range on a different host

I want to redirect incomming requests on a port range ( 30000 to 40000 ) to a different host on a different port range ( 10000-20000 ) mapping them 1 to 1. ( 30000 to 10000, 40000 to 20000 etc ) If the port range is the same i.e.: iptables -t nat -I…
Alexandru Eftimie
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Remove those entries from iptables recent list which are not there in an ipset

I am using iptables recent match for my work as it saves ip addresses and there last seen value which I require. But now I need to remove some entries from the iptables recent list and those entries are there in an ipset. Can anyone tell me is it…
Vinay Tiwary
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Some questions about "-set-xmark" in iptables

I have a rule as following: -A PREROUTING -d 10.228.20.15/32 -p tcp -m tcp --dport 80--tcp-flags FIN,SYN,RST,ACK SYN -j MARK --set-xmark 0x70/0xffffffff The man doc explains --set-xmark as below: Zero out the bits given by mask and XOR value into…
harlan
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iptables redirect from external interface to loopback's port?

I try to redirect port from my lxc-container to loopback. My lxc-container configured with lxcbr1 bridge 11.0.3.1. I try to connect with netcat from host to lxc, and from lxc to host. Success. localhost: # nc -l 1088 lxc: # nc 11.0.3.1…
innocent-world
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Iptables Postrouting with SNAT for a paritcular destination IP

I want to define a rule in iptables for postrouting in ubuntu as below: $IPTABLES -t nat -A POSTROUTING -o $EXTIF -p tcp -d xxx.xx.xx.8 -j SNAT --to-source xxx.xx.xx.238 It means for destination with IP xxx.xx.xx.8 (a oublic IP) , I want its…
Shyamkkhadka
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Cloning and forwarding packets to multiple IP addresses

I'm trying to forward all incoming TCP packets to multiple IP addresses. Setup: A - 10.10.10.10 B - 10.10.10.11 C - 10.10.10.12 D - 10.10.10.13 I want B, C and D to receive (on port 8000) all incoming packets on port 12345 of A. Ideally I wanted A…
rcadima
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Linux nat/iptables configuration for this setup

I have an experimental setup, of 4 linux (CentOS) machines: All 4 machines are internally connected using different networks and can ping eachother directly connected interfaces. However only PC4 has access to internet. I am trying to setup iptable…
Space Rocker
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iptables port forwarding doesn't persist after restart

I have server instance running on amazon ec2. I want to forward from port 80 to 8080 using iptables. Which works fine until restart when it stops forwarding. I have used iptables -t nat -A PREROUTING -p tcp --dport 80 -j REDIRECT --to 8080 to set…
dan
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ip_conntrack_tcp_timeout_established not applied to entire subnet

I've got a nat setup with thousands of devices connected to it. The gateway has its internet provided by eth0 and the devices on the LAN side connect to eth1 on the gateway. I have the following setup with iptables: /sbin/iptables -t nat -A…
Stephen Hankinson
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Direct ALL android traffic through SSH tunnel

I am trying to completely conceal all traffic on my phone from the wireless provider. I would like to do this by directing the traffic through an SSH tunnel to my home router through iptables (not sure if they help?). The phone is rooted and is…
CatZilla
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How to use iptables in an Android application

How can I use iptables in an Android application? I need this for a firewall-like functionality i.e. packet filtering, blocking sites etc. I'm also not sure whether iptables are available in the Android kernel. I previously heard that I'd have to…
Preetam
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