iptables is the userspace command line program used to configure the Linux 2.4.x and 2.6.x IPv4 packet filtering ruleset. It is targeted towards system administrators. Please, when asking a question about iptables, add the output from the following command: iptables -L -v -n

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211 views

Iptables fails to redirect traffic to transparent proxy

My goal was to use ubuntu as a router, with Redsocks serving as a transparent SOCKS proxy redirector. Each machine on my network would have its TCP/UDP traffic redirected to a different port where ...
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0answers
35 views

Prerouting to services with private IP necessary?

I have a server which has a WAN IP and a LAN IP. Without me messing with iptables, any server on the LAN can connect to my ElasticSearch instance on port 9200. But I cannot access the same service on ...
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1answer
36 views

Proxmox with iptables nat is not available

I got an issue with iptables on my virtual machines. I installed proxmox 3.1-21 on my rootserver. I have around 6 IPs linked to my rootserver so i created new 'CT's. The problem is i need to ...
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0answers
54 views

Google Computer Engine Firewall and IpTables

I am very new to to server administration and just discovered that I can use Google Compute Engine to host my website similar to way it works with Linode or Digital Ocean. I am unsure on the following ...
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2answers
111 views

In which order are rules of custom iptables chains evaluated?

I am fairly new to iptables. The picture below shows the order in which chains are evaluated based on my current understanding. If that impression is wrong please let me know. My question is where ...
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2answers
128 views

OpenVPN route remote traffic depending of the subnet

I achieved to setup an OpenVPN to route all the traffic through a remote openvpn server. The OpenVPN server have two interfaces : eth0 -> Internet access eth1 -> Private network : 192.168.1.0/24 ...
0
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1answer
72 views

Local port access blocked by iptables

Although experienced with Linux, I'm new to iptables, having set it up following a Rackspace virtual server setup guide. Using port scans and checking remote access to required ports, I can see all ...
0
votes
2answers
60 views

Is there a way to allow acess to an specific device that is out of my network? [closed]

I’m trying to allow my mobile device to connect from everywhere, Wi-Fi or not to an specific port of my Linux server which is running a webmin service. I’m using iptables to set some rules to which ...
1
vote
1answer
30 views

Upgrade network Class vs Virtualized LAN

We operate on one class C network, let's say 192.168.1.0/24 But the problem is we have 262 devices! I propose upgrading the network to a class B. The opposition proposes purchasing new hardware and ...
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0answers
105 views

NUMIPTENT is too low to add 5333 rules (CSF firewall error)

The VPS iptables rule limit (numiptent) is too low to add 5333 rules (19469/24000) CSF stopped working spontaneously today. Saying it can't start because it can't add 5333 rules to an apparent ...
1
vote
1answer
39 views

AWS EC2 IPTables converts source/dest subnet into ec2.internal hostname?

I have a Debian 6.0.7 x64 AWS EC2 server that I'm running a couple QEMU virtual machines on (don't ask.. long story). I have some IPTables rules to NAT/Forward any traffic (on ports 8080 and 8081) ...
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1answer
106 views

Failed to ping through gateway which is not default gateway

I have the following network interface configuration, eth0: 192.168.78.1/24 eth1: 192.168.254.76/24 (Gateway 192.168.254.1) eth2: 192.168.253.131/24 (Gateway 192.168.253.1) where both gateways ...
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1answer
116 views

iptables on Linux router does not forward DHCP between two LANs

I have an internal network as follows: A Linux system that serves as router, using iptables, with two network cards A client machine A DHCP Server The Router's eth1 is on the same LAN as the ...
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0answers
75 views

Proxy website Centos

everybody would like some help from you I wonder what I can do about it, I would like to redirect an ip from my dedicated server for a website as well? actually would like to do something similar ...
3
votes
1answer
552 views

What is the point of the docker-proxy process? Why is a userspace tcp proxy needed?

I have noticed that there is docker-proxy process running for each published port. What is the purpose of this process? Why is a user space tcp proxy needed for this? $ ps -Af | grep proxy root ...
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2answers
121 views

Centos server will not hold iptables configuration

I have set up a Centos 7 server to run Nagios. By default the OS has pretty draconian iptables rules and a fellow here suggested fixing this by inputing this command: iptables -A IN_public_allow -p ...
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0answers
77 views

Setting up a firewall to route between interfaces on a gateway

I've been trying to setup a firewall on my debian gateway with iptables. The gateway is connected to a a network 12.120.0.0/24 on eth0 behind a NAT and the subnetwork behind it is 12.120.4.0/24 eth1. ...
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votes
1answer
53 views

Cannot curl from the same server when it has PREROUTING ip forwarding

I have a Ubuntu web server that uses iptables PREROUTING to forward port 80 to 8000. So the web process listens on port 8000. Now I want to make a curl from the same server to a web application ...
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0answers
57 views

How to turn a UDP feed on and off?

I have a linux application that is sending a stream of UDP packets to a particular ip and port. I need a way of suppressing this packet stream so the packets never reach the network, with the ability ...
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3answers
518 views

Fail2Ban on CentOS 6.5 Never Bans

Environment: *CentOS 6.5 *Fail2Ban 0.8.14-1 *date outputs the correct date Behavior: Fail2ban starts successfully, but does not create iptables blocks after bad SSH login attempts. I'm only concerned ...
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0answers
475 views

transparent proxy with squid3 dansguardian iptables and one nic

I am attempting to filter my home internet connection through transparent proxy (squid3) and dansguardian . I have the following setup: http://i.stack.imgur.com/5Z3DP.png My Ubuntu Server is ...
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0answers
35 views

linux capability - iptables as child process

I have a process that fork-execlp "iptables-restore file.rules". It looks like it doesnt have the permission since i dont see some of the rules not listed like INPUT DROP after the process executes . ...
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1answer
99 views

csf Integrated User Interface not working

i've installed CSF on ubuntu 14.04 using their official install guide after disabling UFW with the following command : sudo ufw disable then i have modified csf.conf with the following values: ...
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votes
1answer
111 views

Do cellular network adapters (3G/4G/LTE) have MAC addresses?

We are implementing SSH restrictions by restricting by MAC address in iptables. Without the MAC address restrictions, using an app like iSSH, it's easy to access my server on the go to check on it's ...
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1answer
51 views

iptables - ignoring -i

In my iptables rules, I want to accept only lo but drop every other interface. but when I execute this command : -A INPUT -i lo -j ACCEPT it is not specifying interface lo but it is accepting all ...
0
votes
1answer
116 views

PHP/Ruby captive portal first domain seems cached

I have created a captive portal with iptables I use what many people seem to use : Users can request DNS, packet marked as 99. 99 means no internet else the user does have access. When a user ...
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votes
1answer
100 views

ssh on eth0, everything else on eth1 [closed]

I wouldn't even consider myself an iptables novice user, so I was wondering if someone could please help me to do this: I want to be able to ssh into one of my servers using the eth0 network ...
2
votes
1answer
92 views

iptables: match only the first packet of established TCP-connection

In my Apache-logfiles I find a lot of entries that contain "GET /w00tw00t.at.ISC.SANS.DFind:) HTTP/1.1" 400 or similar crap. They come from non-RFC2616-connections (HTTP/1.1 without hostname). I ...
0
votes
1answer
53 views

I want to proxy only HTTP but I'm not sure what to do with HTTPS traffic

I have a DNS server that resolves all traffic to my Squid server that will proxy all HTTP traffic transparently (it must be transparent or it will drop a invalid url error) which works great. The ...
0
votes
1answer
73 views

ip table rules for allow memcache connections

What do the following rules mean? The rules were put in by a sysadmin and seem to be working, but I think there is some redundancy in them. My goal is to allow connections on port 11211. This is on a ...
0
votes
1answer
189 views

Port forwarding with iptables -> connection refused

I am trying to redirect requests to my local IP (10.42.42.152) on port 80 to a remote server, e.g. google.com (173.194.113.104:80). The remote server is up, ip_forward is enabled but I only get ...
1
vote
1answer
110 views

Port open or not?

I am trying to access the Atlassian Crowd server to configure it, which is listening on port 8095. I can access it from localhost. If I disable the firewall (iptables stop), I can access from a remote ...
2
votes
1answer
71 views

Stateless NAT with CentOS 6

I'm looking to set up the following: ---[IVR 1] | (internet)----[CentOS box]---+---[IVR 2] | ...
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0answers
37 views

tun0 not listening traffic on a simple vpn example

I tried to setup a simple vpn test server on Ubuntu 12.04, called ToyVPNServer. The guide is simple and I take test for days but still cannot get connected. The inspection result is showing the issue ...
0
votes
1answer
30 views

make specified ip log filtering from port mirroring input with iptables [closed]

I have difficult to create an iptables rule of traffic coming from a switch that is configured as port mirroring. I checked if the traffic from my switch is sent with tcpdump -> Tcpdump detects ...
0
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0answers
67 views

Reroute outgoing port through other server

I want to run a xmpp-server on another IP than the A-record of the domain points to. +--------+ +--------+ +--------------+ | xmpp | -----> | web | -----> | internet | | ...
0
votes
1answer
40 views

Iptables working without configuration

I am currently going to port a Red Hat 6.4 machine and I need its firewall configuration, but something is going on. iptables -L shows a list of rules as expected, but at the same time I can't find ...
0
votes
0answers
33 views

Can't connect to Tomcat

I an new to Tomcat and having some problems - I have installed Tomcat 7 and it is running and set to use port 8080 in server.xml. I have opened port 8080 in iptables (and saved iptables) but I cannot ...
1
vote
1answer
77 views

iptables + postfix cant send email

Recently my host provider sent me a letter about some sort of attack from my server. I'm not into security so i found some tutorial and closed all unused ports with iptables. Here is my iptables ...
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votes
1answer
76 views

Something is filtering 27017 port even then firewall is not working

Good day, i' trying to move mongodb database to separate VPS from application, but VPS was pre-configured not by me. I have instance with running mongodb on 27017 port: COMMAND PID USER FD ...
0
votes
1answer
107 views

ssh tunneling not working due to strict iptables

my iptables are set so that I can only allow ssh connections. I tried ssh tunneling and I can connect to my sever, but after when I try using my server as a proxy on firefox, pages try to load ...
0
votes
1answer
117 views

Iptables drop outgoing HTTPs GET request matches string in payload [closed]

I'm using CentOS 5.8(final), kernel 2.6.18-308.8.2, iptables v1.3.5 I want to block a HTTPs POST/GET request to outside which matches a string (defined as ABCxyz) in the POST/GET payload. I tried to ...
0
votes
1answer
42 views

QEMU guest can access HTTPS sites, but not HTTP

So I'm configuring a QEMU guest on my Debian Wheezy server, using virt-manager. As guest I've installed Ubuntu 14.04.1 server. The server contains the following iptables rule: iptables -t nat -A ...
0
votes
1answer
73 views

Data only seems to go one way on ethernet over usb connection [closed]

I have a router+modem combo connected via ethernet to a raspberry pi (this part works fine) The pi has a usb wifi device plugged in, and runs hostapd, does NAT and provides internet to a household. ...
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votes
0answers
80 views

Why HLS streaming bypass connlimit iptables rule?

excuse me, i have this situation: I need to set limits to the simultaneous connections to a server to enable only X number of viewers of a stream at any time. To make the video streams we are using ...
0
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1answer
264 views

Fail2Ban - Iptables - Set does not exist

I have a very strange problem with fail2ban/iptables. Something is not working right, but I can't figoure out what. I have added this conf & and filter for fail2ban: [wordpress-register] enabled ...
1
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0answers
103 views

shorewall can'T start: UNTRACKED state requires Raw Table in your kernel and iptables

I'm trying setting up my firewall and installed and configured shorewall. Unfortunately I tried to directly configure iptables first, but this didn't work. When I start shorewall, I get this messages ...
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votes
1answer
26 views

Application protocol-based port forwarding/redirection [closed]

I need to split traffic on port 80 between HTTP and non-HTTP, and internally forward HTTP traffic to a port nginx will listen to, and non-HTTP traffic to port 22. Does anyone know of a piece of ...
0
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1answer
139 views

TCP packets not reaching app, iptables dropping?

We are occasionally, but not consistently, experiencing a weird network stack issue. Rebooting the server in question clears it up. It happens as follows (gleaned through tcpdump on the server): ...
0
votes
1answer
67 views

Can't open ports to ouside

I need to open my webserver to internet. I have no idea whats wrong with my config but no ports opened to internet, and server does not respond to ping. I have debian squeeze webserver with following ...