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

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VirtualBox, Ubuntu clients, internal network proxy to supply internet

Probably this question was asked many times, but I seem to be unable to find proper solution. Here is my setup: Two virtual machines(Ubuntu 12.04) M1 and M2. M1 has 2 network adapters: eth0 set ...
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What is MASQUERADE in the context of iptables?

In Iptables many times I see the target MASQUERADE. What is that. I searched and find lots of things. But I need some one explain me what MASQUERADE is in a so easy way? **If you bring an example ...
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82 views

Redirecting external ports to local ip

I have a ubuntu 13.10 server and a registered domain name. I have a web server on my 192.168.24.1 machine and a ftp server on my 192.168.24.2. Using iptables I want: 1) people who write : ...
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Ubuntu 13.10 allows connections from LAN but not from outside LAN

SSH ports configured to all 22 and another one. I can connect from another Linux/Windows workstations on my home LAN no problem. Same thing for nomachines nx server. Teamviewer connects with no ...
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514 views

Not pinging with host-name and can't ssh using hostname [duplicate]

I have setuped a DNS server in Centos6.5 and its working with every client machines other than ubuntu, now i have issue with ubuntu While im trying to ping from desktop machine to DNS server as ping ...
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Is someone trying to hack into my server? What can I do?

A few weeks ago I posted a question here about some ssh issues I was having with an Ubuntu 12.04 box. Fast forward to today and I am trying to allow someone else access to the machine, but they keep ...
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1answer
65 views

iptables command to give internet to my guest OS via virtual box

Based on this link there is a difference between Host-only network and NAT. So I want to set the LAN connection between my host -14.04 ubuntu- and my guest XP by Host-only network. How I can give ...
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1answer
347 views

Firewall rules for transmission

I have transmission installed, which listens on the default port 51413. I have tried opening everything for this port. iptables: Chain INPUT (policy ACCEPT) target prot opt source ...
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70 views

How to block ip forwarding for specific remote ip address

I use ubuntu as gateway for several hosts. I need advise how to block ip forwarding for specific ip address or specific ip range? I tried to block ip via ufw deny rules, but it looks like ip ...
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1answer
42 views

iptables ruleset blocking all network activity?

I've gone through numerous trial and error to recently discover that my iptables result is the culprit of blocking all LAN and WAN activity. I know this, because if I comment out the last line in my ...
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101 views

Port forwarding out multiple VLAN interfaces that have same IP address

So I have an Ubuntu machine with multiple VLAN on an interface eth1 and each VLAN has the same IP address (172.16.0.2). I need to be able to simultaneously telnet into a rack of devices that are also ...
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1answer
316 views

Where is /etc/sysconfig/iptables-config in 14.04

Where is /etc/sysconfig/iptables-config in 14.04 I can't comment in this thread because I do not have a reputation of 50 Configuration of iptables (verfication, actives services, allow FTP)
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Something is not quite right with these iptables' rules?

I found this after googling: iptables -A INPUT -i lo -j ACCEPT iptables -A OUTPUT -o lo -j ACCEPT #allow loopback access iptables -A OUTPUT -d 255.255.255.255 -j ACCEPT #make sure you can communicate ...
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1answer
420 views

Dnat prerouting does not work on Ubuntu 14.04

I've got a Ubuntu 14.04 server used as firewall, router, dhcp, dns and proxy. Everything works properly from inside to the internet, but the forwarding from outside to the inside network doesn't work. ...
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120 views

Ping to Honeyd virtual host replying Destination Host Unreachable

I have installed and am running honeyd and farpd successfully on Ubuntu 13.10. But, now the problem is: Pinging the virtual host from honeyd host (and from any other local network machine) #ping ...
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2answers
5k views

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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1answer
254 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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2answers
127 views

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
306 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
629 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
40 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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137 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
594 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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55 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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213 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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102 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
90 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
665 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
1k 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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1answer
69 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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218 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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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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187 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
61 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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67 views

Port won't open! [duplicate]

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
113 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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31 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
63 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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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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75 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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75 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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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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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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226 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
464 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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154 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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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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77 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
73 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
1k 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 ...