Iptables is used to set up, maintain, and inspect the tables of IP packet filter rules in the Linux kernel.

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ubuntu 14.04 default firewall rules

I would like to know exactly which scripts are responsible for default iptables rules (no ufw, no gufw) in Ubuntu Server 14.04. After fresh installation even with ufw disabled (by default) there are ...
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4 views

Squid as proxy is only allowing https traffic

I have installed Squid with Dansguardian and configured it exactly as instructed here. It works fine for https traffic, which is allowed through just fine. However, squid doesn't allow any http ...
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How do I with ufw deny all outgoing ports excepting the ones I need?

I did the following: ufw default deny outgoing, sudo ufw allow out 80 which I thought would let me use the Internet but didn't can y'all help? Also are there any other ports used by Ubuntu for which ...
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1answer
24 views

what does this mean “80/tcp filtered http”

Our linux server(ubuntu) stop listing on port 80. this is what i got : PORT STATE SERVICE 22/tcp open ssh 80/tcp filtered http what does this "80/tcp filtered http" means? What ...
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1answer
21 views

How to make modprobe ip_conntrack_ftp persist a reboot

Sorry if this is a stupid question, but to get outbound active FTP connections through our firewall we need to run the following: sudo modprobe ip_conntrack_ftp I learned this trick from ...
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1answer
13 views

Ubuntu forward ports, default state, forwarding not working?

im running ubuntu 12.04.4 server. I been googling the nett for answers, but could not find any.. I would like accsess a few web-gui's on my server. I have forwarder the ports in my router, worked when ...
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105 views

IptabLes and IptabLex hack? [closed]

I am running a Ubuntu 12.04.2 LTS. At a certain moment the server started to make a connection to a server with IP address 61.174.41.15 on port 9005 (tcp). We saw this happening starting on 3/4/2014 ...
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54 views

Use squid3 on same machine in tor browser 3.5

I'm using Tor Browser bundle 3.5.3 and squid3 (version 3.3.8) on Ubuntu 13.10 as transparent HTTP proxy on the same machine (i.e. not usual setup on gateway). I redirect HTTP request through squid ...
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1answer
28 views

redirect port 80 to 8080 and make it work on local machine

I redirected traffic for port 80 to 8080 on my machine with sudo iptables -A PREROUTING -t nat -p tcp --dport 80 -j REDIRECT --to-port 8080 It works fine for all world except my own machine. I am ...
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Can I access the 4 addresses provided in the mac header of wirless 802.11?

I am writing a module that hooks a function on OUTPUT hook of the kernel netfilter. I want to access the complete information inside the mac header of the packet esp all the 4 addresses or in some ...
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19 views

using iptables to restrict VPN user access to internal network

So say I have a set up in which a single server running virtual machines and a pptpd server. The pptpd server hands out IP addresses in the 192.168.0.0/24 range. The virtual machines have IP ...
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1answer
63 views

Iptables and bind9 to forward to google's dns

Hello i have a very hard time on getting along with iptables and bind9 as my internal network dns server. It's configured to forward my queries to google's dns (8.8.8.8). The main problem is i can't ...
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1answer
39 views

Ubuntu 12.04 secondary IP externally inaccesible

I have added a secondary IP to my virtual server, Ubuntu 12.04 running in OpenVZ virtual host. I used ip addr add xx.xxx.168.95/32 label venet0:1 dev venet0. When I do ifconfig the IP shows up below ...
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1answer
27 views

Outbound SMTP redirect

How would I go about redirecting all outbound email on port 25 of my server to port 25 on another server using iptables. I have tried a few rules already and none of them are working. Would ...
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1answer
48 views

Can curl localhost, but can't access port 80 from LAN

I can't find an answer to this question anywhere. I have ssh access set up, and can tunnel into my server. When on the server, I can curl localhost and get a response: curl localhost However, when ...
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1answer
99 views

linux command to prevent dos attack by using netstat and iptables

I want to DROP more than 200 requests per ip to prevent ddos attack. this is command that i used to detect requests count per ip : netstat -alpn | grep :80 | awk '{print $5}' |awk -F: '{print ...
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25 views

Need help to make this file work in iptables

I came across the following example of how to use iptables to block internet access when the VPN connection is terminated abruptly: iptables -A INPUT -i lo -j ACCEPT iptables -A OUTPUT -o lo -j ...
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60 views

IPTABLES: Deny access to domain to everyone except a small list of IPs

I have a couple of public webservers and some home based Ubuntu machines. I maintain a couple of domains specifically to monitor things like MySQL and Memcache. Ideally I'd be able to connect to ...
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2answers
47 views

How do I add a new user with specific configuration files?

I am new to Ubuntu and *nix OSes. I have just installed the latest stable version of Ubuntu on my computer. During the installation process, I created a user account. Let us call it N1. Just to try ...
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107 views

help with iptables to redirect all traffic to local proxy server and output it

First I could say I am not so good at internet management and all this stuff is very confusing me... to my laptop, internet comes from wlan2 interface. It is being shared through interface eth0. ...
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1answer
31 views

enable port 9696 on ubuntu server

I am using ubuntu server lts 12.04 on vmware virtual machine. I need to enable port 9696 which is blocked or filtered. When i use the nc -v -w 1 localhost -z 9696 command it shows me the following ...
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45 views

Port won't open!

I have a server that want to allow connections into it through port 25565, but when I test on http://www.yougetsignal.com/tools/open-ports/ it says they are closed? I have no outfacing interface ...
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1answer
90 views

How do I use NAT in iptables

I have a domain set for my server, let's say example.com which is being forwarded by my router and is linked to my external IP 11.111.111.111 and it works fine if I ping the domain, or I do a lookup, ...
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25 views

Why are the ports not open?

I have a server which can be pinged, and if I look it up, you can see it's IP address. Although, I have forwarded the ports necessary (25565) on my router and I still can't listen on that port. My ...
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1answer
39 views

Can I have a dhcp interface in /etc/network/interfaces?

I have an interface already configured for an internal interface, which is static under eth0. My question is, can I create a dynamic outfacing interface under eth1. The reason I want to so this is ...
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48 views

how to set up iptables for dyndns server?

I have a server running with a dhcp public IP and ddclient updating my hostname from my public IP whenever it changes. My ISP has a feature for dyndns, so my router should automatically map my public ...
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17 views

libipq not supported in Ubuntu 12.04 LTS

I have the requirement of altering packets as a part of my University's research project and came across two libraries. which are libnetfilter_queue and libipq which is the deprecated version. ...
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44 views

Iptables help with server on 12.04?

I am trying to create a Minecraft server with port 25565 for me and my friends to access. I used to run one on my mac, where I would change the config for my firewall to allow connections through ...
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16 views

Using server as controlled switch

I have an Ubuntu server with 3 NICs installed. I have two classrooms. I want to control the two classrooms with IPtables separately. My problem is that I can't (bridge eth0 to eth1) and (bridge eth0 ...
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23 views

How do I make an outfacing dhcp interface?

I am running Ubuntu Desktop 12.04 and I want to make an outfacing interface that hands out external IPs mapped to my hostname for ease of use with Iptables. How should I configure this?
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102 views

How to log firewall logs to a remote Syslog server

After much reading and unsucessful attempts, I do not manage to send some of my firewall logs to a remote server. Here is my setup: The remote server is a synology NAS, on which the syslog server ...
0
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1answer
156 views

Ubuntu and OpenVPN

Im trying to setup OpenVPN on Ubuntu and I can't get internet access when I connect. Only local ip of server is reachable (10.8.0.1) Please Help. My configurations: Server.conf ...
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49 views

Corosync & Pacemaker IPTables Rules

When using Corosync with two rings via multi-cast addresses 226.94.1.1 (Port 5405) & 226.94.1.2 (Port 5406) what iptables rules are required to allow two nodes to communicate optimally without ...
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22 views

A more complex iptables set of rules

I want to make a script that sees if a number of connection attempts are made from one or more IPs ($CT_MULTIPLE_IP_THRESHOLD) in an ammount of time ($CT_TIME). If this happens, than in that ammount ...
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42 views

How do I allow connections through my external IP in iptables?

Let's say I have an internal address of 192.168.0.2 and an external address of 1.222.333.4 My external IP should, by default, be mapped to my internal IP. But how should I allow connections into my ...
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1answer
38 views

How to map my ipv4 address to external address in iptables

I want to run a minecraft server (port 25565) and have it send to my external address for others to play, then to my hostname (I am assuming this is automatic - Do I need a rule for this too?). But I ...
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1answer
42 views

persist port routing from 80 to 8080

I use amazon EC2 instance which works via ubuntu. By default according security restrictions I can't bin my application to port 80, so I just bind it port 8080 and then set routing redirect from port ...
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0answers
18 views

How do I add an auto updating file with DynDns?

I am trying to map my internal IP to my external IP. I have no option for a static IP and wanted to achieve my iptables configuration through Webmin. So What I thought was, to simplify the iptables ...
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1answer
63 views

How to block all traffic except for browsing?

Sorry for the paranoid question but is it possible to block all connections except for Firefox and updates? And if so does someone got a terminal code for it?
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2answers
60 views

Where did I fail with my basic iptables setup?

I installed iptables on a VPS (Virtual Private Server from openVZ) - Linux 2.6.32-24-pve #1 SMP Fri Sep 13 07:29:30 CEST 2013 i686 GNU/Linux. I also installed: apt-get install iptables-persistent ...
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1answer
51 views

UFW locks me out of server everytime I run it

Background: I'm setting up a new 12.04 instance on a VPS with a new provider.The VPS provider only offers a 32bit image but that really shouldn't matter here. I have no local access to the machine and ...
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3answers
72 views

Very easy iptables tutorial?

Where to find a easy "iptables for dummies" tutorial? I know NOTHING about it and basically I need to allow only http, ssh and ftp connections... thank you all
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54 views

SSL and localhost issue

Hi I am new in Linux and Ubuntu(13.10) and have reached stop point of my configuration. the configuration of my server is apache2 with sslv3,tlsv1 only on 443(iptables prerouting 80 to 443) and ...
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1answer
52 views

How to limit the device's internet speed but not lan in wifi lan network in Ubuntu

Environment: A wifi lan network with ip 172.16.0.1 and name br0; A host in wifi lan with ip 172.16.2.12; A ethernet network interface with ip 192.168.1.133, name eth0; How can I limit host A's ...
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1answer
24 views

iptables, order of rules - do I understand it right?

I would like to configure my VPS in the way that it ONLY accepts connections from outside on port 22 (where sshd listens) and ICMP requests. Everything else from outside should be rejected. Inside the ...
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Connection on interesting ports (25, 110 etc) is NOT refused. Who/what accepted it?

I am running a VPS with Ubuntu 12.04. The only payload is reachable for me via SSH at port 2244, all fine. Running a scan from outside (angryip), I see that quite some ports are responsive ...
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1answer
83 views

Fail2Ban/IPTables & Pure-Ftpd

I have pure-ftpd running on web server with Fail2Ban. Fail2Ban is letting apache2 connections in but are denying any FTP connection from anything but local host. I have attempted to modify the ...
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1answer
39 views

iptables configursation question

Purely as an academic exercise in an attempt to simply learn, I have been playing with iptables. Spent a few days on this so far and I think I now have a good understanding of how it all works. I ...
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0answers
43 views

Forward web request to another computer

I have one notebook and two servers: ip = 172.17.0.2 (I have installed nginx here) ip = 172.17.0.3 (There is nothing here, but I can ping 172.17.0.2 from here) I open browser on my notebook, open ...
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36 views

Ubuntu Port 80 from some hosts not reachable

I have an ubuntu-server in a LAN. Whenever I try to run a Web-Server like apache2, or any other server like node.js on port 80 it is only reachable for some hosts in the network (the browser is ...