Iptables is a module that provides the Linux operating system functions of firewall, NAT and logging of data traveling over a computer network.

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slow internet access when routing via a server (both using iptables NAT and ssh tunnelling)

I have a spare computer powered by a dual core intel atom N550 CPU and 2GB RAM (I will refer this as "the server"). It is running lubuntu 14.10 x86 (32 bit) with lightdm service disabled (hence, no ...
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block specific port access for VPN users from iptables setting

I set up an L2tp VPN on a vps server to provide service to users. But I don't want users to connect web except the way I allow them. To make it simple, for example,I don't want them to access the port ...
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8 views

How do you force linux to treat a tcp packet as if it were at the destination ip?

The situation: A tcp packet arrives on eth0 with destination 8.8.8.8. This packet meets some criteria that makes me want to intercept it (lets say I am interested in all packets from source ...
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10 views

VPN does not reconnect (cannot resolve host address)

maybe someone can help me: At the moment i am trying to configure a fail-safe VPN connection to a commercial VPN provider on a virtual machine. This is working fine, until my router wants to reset my ...
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14 views

DDWRT - OpenVPN connects, but can't communicate

This seems to be a popular topic, but I can't find any solution to the same problem I am having. Here's the setup: I have a DD-WRT router (build 14896) on a linksys WRT54GL. I have one file server ...
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7 views

how to capture “DROP”ped packets on OUTPUT of iptables?

having a fairly complex OUTPUT processing on iptables, how does one go about capturing / displaying (at least similarly to how tcpdump captures them) the packets that were to leave through an ...
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9 views

Webserver connected to VPN: Way of incoming traffic?

All apologies if my question is unclear from the start; but: I have a webserver which is a rented root-server at a provider. It is running a webshop that is openly accessible. It is necessary to ...
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Round-Robin Outbound Source IPv6 Iptables

I'm trying to do this: http://linuxbutler.com/tcpip-outbound-round-robin-load-balancing-iptables/ But with IPv6. It doesn't work, however. Seems nat doesn't exist in IPv6. Can you guys help me out ...
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21 views

Iptables rules suddenly not working

I'm trying to set up a webserver using an Odroid U3; as OS I have Debian 7.4. The issue came when trying to load the iptables rules with iptables-persistent. I'm using the same file with rules I've ...
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26 views

Iptables stops the network after a while

I have 3 dedicated servers (same hardware Supermicro X8STi and same bios) with CeontOS 7 Linux 64Bit and I'm having a problem with one of them, with iptables to be precise. When I change the policy ...
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25 views

Block archive.today From Crawling My Site?

My website is being scraped by archive.today. This site is similar to the reputable archive.org, but archive.today does not obey robots.txt, spoofs a generic user-agent and tried to hide its IPs. The ...
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35 views

Routing traffic around VPN

I recently setup a OpenVPN client on my HTPC, however once I connected to the VPN server I was no longer able to remotely SSH or connect to the other servers I had running on the HTPC. I followed ...
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34 views

iptables always needs restart

I have a CentOS 7 PC, on which I'm using iptables. I have an Oracle 11gR2 instance on that PC and I need to access is from other PCs in the LAN. My /etc/sysconfig/iptables: # Generated by ...
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19 views

blocking port54370 tomato router

I'am having a huge amount of outbound traffic on my network. source port is 54370. Jan 16 00:34:55 unknown user.warn kernel: ACCEPT IN=br0 OUT=vlan1 SRC=192.168.11.88 DST=192.168.0.11 LEN=116 ...
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20 views

How to create two different open VPN link between two hosts?

I want to create OpenVPN tunnel between two Ubuntu 12.10 hosts which has two interfaces, say: Host1: eth0, eth1 Host2: eth0, eth1 A tunnel is wanted between: Host1 (eth0) <-> Host 2 (eth0) Host1 ...
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12 views

how to Connection from a remote system to another via multiple squid proxies?

I have a setup that sending data from host 1 to host 2 via proxy running different middle hosts. I don't want just routing packets in middlehost and send to destination. The reason is I run new MPTCP ...
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79 views

Can ping but can't connect (curl, wget, apt-get, etc.) (rasberry pi server)

Background: I am trying to set up a rasberry pi server. Everything was going well and my pi could apt-get update etc, until I got the port forwarding to work and ssh to work outside of the LAN. I ...
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78 views

iptables out bound port to remote mysql

Following is my iptables file on my centos, I am unable to open 3306 port to connect to remote mysql server. I dont know what I am doing wrong although it looks fairly simple. When I stop the iptable ...
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26 views

How do I reroute a DNS request?

I have a Technicolor (Thomson) Modem, and I want to reroute a DNS request coming from a specific IP to another DNS server. I have an iptables command looking like this: iptables -I PREROUTING -t nat ...
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18 views

Iptables rules for host-only interface

I'm in this situation. I have an host machine running Ubuntu and 2 virtual machines using VirtualBox. They're connected via the host-only option on the virtual interface "vboxnet0". What I want to ...
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14 views

How to acchieve what http_proxy environment variable does for all traffic leaving the system?

I set up a trafficserver (5.1.2) instance as HTTP cache on a machine in my local network and now I'm looking for a way to enforce the usage of the proxy for HTTP requests to the outside world on port ...
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33 views

Share Internet through Arch Linux VM

I'm working with a LAN which is behind a router that I don't control. The router admin has allowed internet access to one IP address 192.168.0.50. I would like to create an arch linux VM at that ip ...
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21 views

Iptables newbie pain

I got a host (WINDOW7) and a guest (DEBIAN7.7) virtualized by VirtualBox. I configure an eth1 interface as host-only. My host can ping the guest and vice-versa, host can connect via ssh too. Now I ...
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32 views

Limit connections per second with iptables/ufw

How can I tweak the following entries to allow more requests per second? Maximum hitcount is 20 if you do not edit some other config files. The entry of my /etc/ufw/before.rules file -A ...
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96 views

Port Forward/Proxy SSH inside DD-WRT

I have configured an SSH tunnel on my DD-WRT router using the default port 22. I would like to open another port on my router as a proxy port for SSH, say port 80, in case a firewall prevents me from ...
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IpTables: rule to allowing outgoing traffic

I need rule to allowing outgoing traffic from intranet addresses 192.168.X.X to foreign addresses 123.123.123.0-63 and by using tcp Protocol. Sorry for bad english Thanks
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19 views

Remove iptables rules from recovery system?

I have a remote dedicated server and accidentally added some iptables rules that killed network access. I am only able to access SSH in recovery mode, which gives me access to the filesystem. I can't ...
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45 views

Can a Linux machine have two the same IP addresses on different interfaces/networks?

Is it possible to have two the same IP addresses and subnets assigned from two different interfaces/networks? How would such machine behave? How would route table look like?
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65 views

Blocking 127.0.0.1 in iptables?

I'm in the process of setting up some rules for iptables. Not wanting to make any errors I am currently only logging activity. The logs have shown a number of entries for 127.0.0.1 hitting my rules: ...
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56 views

FTP does not work properly when connected to OpenVPN

I am connected to an OpenVPN server and would like to list all files on a FTP server. ftp> ls 500 I won't open a connection to 10.125.1.20 (only to 31.x.x.100) ftp: bind: Address already in use ...
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Cannot retrieve http sites when using OpenVPN, but https sites work just fine. Why?

I am using a VPN provider that uses OpenVPN. I don´t wont any other traffic leave my computer so I have set up my iptables like this: iptables -P INPUT DROP iptables -P FORWARD DROP iptables -P ...
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How to set up a hotspot with socks5 proxy

I have a laptop with linux installed on it. The laptop has two network interfaces: eth0 and wlan0. Normally I surf the Internet through eth0, and I've successfully set up a hotspot in linux for my ...
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33 views

How to print iptable firewall rules?

How does one print or dump the firewall rules being used by iptables in an effort to trouble shoot connection problems? I'm fairly certain its going to include -L or --list, but I'm not sure of other ...
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1answer
45 views

iptables - UDP Packets from unknown IP addresses

I'm really new to basic systems administration, and this question is a bit difficult for me to Google. I'm setting up a small raspberry pi server for my own personal use, to teach myself some basic ...
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32 views

What minimum'allows' should be used in iptables rules?

I have a Ubuntu 14.04 server which has two Ethernet ports: eth0 directly connects with a custom camera and eth1 connects via LAN cable to a wireless router. I had been developing a web application ...
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2answers
87 views

Openvpn connects and responds to ping but no internet access

I have an openvpn server running on raspian and a tunnelblick client on osx. I can connect to the VPN just fine but I have no intenet access. The server responds to ping just fine and the port is open ...
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49 views

how to save iptables rules permanently?

I want to keep some iptables rules permanence, so I just only add the rules manually: /sbin/iptables -I OUTPUT -p tcp --sport 80 -j QUEUE I am sure that the command works, because I could see it ...
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124 views

iptables duplicate traffic to another ip

This blog post has a template iptables rule to forward traffic, to and from the router to another ip address. iptables -t mangle -A POSTROUTING \ -d [IP to spy on] \ -j ROUTE –tee –gw ...
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25 views

Iptables: Filtering string encrypted by ssl

I need to filter (send to BANRULES set) incoming http/https packets with a certain string (matchword). I do it easy when ssl is not in use (port 80): iptables -A INPUT -p tcp -m tcp --dport 80 -m ...
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How do I set Input interface is output interface

I have eth0 with IP X.X.X.X and eth0:0 with IP Y.Y.Y.Y. My goal is if I connect to eth0 then output ip shoud be X.X.X.X and if I connect to eth0:0 the output ip should be Y.Y.Y.Y. Example: VPN ...
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21 views

iptables INPUT command

On a ubuntu1, this is iptables command: sudo iptables -A INPUT -p icmp -j DROP so on the other computer (xp1) I can not ping the ubuntu1.So this is OK. But On ubutnu I [[ can ]] ping xp1. and I ...
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104 views

Configuring IPTables to exclude webhost from VPN tunnel

I have a Raspberry Pi running as a server for my webhost. Raspberry pi is connected to a VPN service 24/7. Due to this, I am unable to connect to my webhost using my public IP address issued by my ...
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1answer
37 views

How to forward http request to a proxy server?

I have an Internet Linux server and my client computer (running windows) accesses internet via a SSH tunnel to the the server. Now for some reason this server can only accesses internet by a http ...
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1answer
29 views

Clients unblocking AWS S3 Content on their firewall

I have a website that serves out user generated content from AWS S3. I have a client that wants to use our website from behind a firewall. They are asking me to provide them with a static IP Address ...
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44 views

Creating a login portal for my WiFi

Me and my room mate often have a lot of friends come over to our apartment to play games and what not. So we are talking a lot of devices connecting to my router (cell phones, tablets, laptops etc .. ...
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Nodejs remote debugging ports closed

I have a problem with nodejs remote debugging. I'm using centos on remote server and phpstorm on my PC. When I open putty I type the command: node --debug-brk=5858 main_server.js, and get the ...
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28 views

DD-WRT route between vlan2:1 and vlan2

I've been trying to configure a Netgear R7000 with DD-WRT on board. My problem is the fact I have a private ip assigned to the WAN (vlan2) and a public ip assigned to vlan2:1 If I use only iptables ...
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29 views

iptables settings for Tomato

I am trying to figure out the iptables settings for my router. Right now I have two networks, a home network on br0 and eth1, and a guest wifi on br1. Home IP addresses are on 192.168.1.x, and guest ...
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Access two web servers (VPS and Windows Server) through the same IP (PUBLIC AND VPN) using VPN

I have two servers: a hosted VPS with a website on port 80 and a home server running Windows 7. The home server is running WAMP on port 88, which works on my home's public and local IPs. When ...
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How can I control specific traffic like UDP traffic with iptables on ubuntu?

If for example I would like to send just the UDP traffic to an IP-address, is it possible to do this with iptables ?