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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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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19 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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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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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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allow vpn and internet ports block everything else [duplicate]

can someone help me write ip tables rule for allow vpn route all traffic to Vpn Internet and block everything else pings so allow vpn and Internet port 80 block everything else thanks for help
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38 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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41 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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25 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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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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63 views

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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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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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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27 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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15 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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37 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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25 views

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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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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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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26 views

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 ?
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Modify incoming packets before forwarding in Linux

I’m using a Linux (Debian based) system on which IP forwarding is enabled (/proc/sys/net/ipv4/ip_forward is set to 1). I can read the incoming packets using a raw sockets program, but I want to modify ...
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How to Ban an IP address automatically in ubuntu 12.04 when it sends specific packet to server?

I run a game server and someone is attacking with fake players. I want to ban him automatically in Ubuntu V P S. Any IPtables command or program that can accomplish this task? If it's not possible ...
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47 views

linux: how to troubleshoot forwarded port?

My home internet connection has a static IP address (eg: 123.123.123.123) I have configured my router to forward port 9000 to an internal host (192.168.1.101), which is running Ubuntu 14-04. I run ...
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30 views

Block traffic to LAN but allow traffic to Internet (iptables)

On my home network I am setting up a CentOS server that will be used by about a dozen or so for educational purposes - e.g. learn how to use the Linux shell and host websites, among other things. I ...
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24 views

About network traffic control

I have a satellite internet connection -> a pretty nice 8 processor server with 64gb of ram, running debian 7.7, two lan ports, one connected to the gateway, the other to the wifi router, wifi to all ...
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42 views

Map remote host to local ip (linux)

How can I map remote host to local ip? For example: If I map google.com to ip 192.168.1.15 so when i ping 192.168.1.15 i get forwarded response from google.com Maybe Iptables or something?
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36 views

Connections from virtual host to internet OK, but to rest of LAN, broken

In a notebook running Ubuntu 14.04 I have installed VirtualBox and created a virtual server with Windows 7. The PC is connected to a 192.168.x.y LAN. The virtual server is in a host-only network with ...
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25 views

Config to make only pcap receive packet

I am trying to use pcap to modify the packet before sending it out. For example, I have a server (running Ubuntu) listening on port 8000. Before it sends out SYN-ACK for incoming SYN packet, I am ...
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51 views

iptables snat does not change source IP

I am on ubuntu (with IP 10.0.0.1) trying to snat packets going out from port 9090. I want to change the source IP to 10.0.0.2 I have added the following rule through iptables: # iptables -t nat -A ...
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35 views

Debian 7 - iptables 'filter' not supported?

Am attempting to forward/ masquerade connections from WLAN0 to ETH0 as follows: sudo iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE sudo iptables -A FORWARD -i eth0 -o wlan0 -m state --state ...
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Packets are delivered to the host, which has the (dst) IP, but the application bound to the IP/port never see the packets

I have an iMac and a dd-wrt router. On the Mac side of things I have a proxy executable that I wish to use, but I've been unable to figure out how to make pf forward packets to the same host. ...
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62 views

IpTables -j REJECT to instantly block the loading on user browser

I have been searching for a solution to notify the browser on user that the request is Rejected so stop loading it. Because I have blocked facebook and every page that have a facebook plugin is ...
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44 views

Cannot SSH on machine behind NAT. DD-WRT router

I'm trying to remote access my home Debian from my other office. The home Debian is behind a DD-WRT router, connected from a ADSL modem (Yeh, it's dynamic IP but I have someone to tell me the WAN ...
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How to block network traffic on ubuntu gateway via arp table

I have a network with 80 PC and a ubuntu 12.04 as GW. For security reason I want to limit the Computers connected on this network using an ARP precompiled table. In other words I want a tool that ...
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51 views

Routing specific port ranges to specific gateway on Asus AC68 router using iptables and ip route

Linux noob here. I was hoping someone could help me with configuring some routing rules on my router, an Asus AC68. The router is connected to two gateways, wan0_gateway and wan1_gateway. I have ...
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27 views

Why is the TCP open but not the UDP?

I'm setting up a game server and I have a bunch of ports forwarded already (all in use). So I'm putting one into /etc/ppp/firewall-masq, which is full of iptables rules. The game server is served by a ...
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29 views

IPTABLES NAT port forwarding

I'm trying to setup a Linux box to act as a very simple 2 NIC router. I've read over the instructions on the bot Archlinux and Gentoo wikis and gotten the same result, masquerading works but not port ...
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Preserve NAT mappings across reboot

My Linux router is able to reboot and reconnect all network interfaces pretty fast (~10 seconds, thanks to systemd and a SSD disk), and comes up with the same IP addresses. Unfortunately the reboot ...
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32 views

Trouble with last DROP rule in iptables

Let's say I want four ports to be opened for any incoming packets so I made this ruleset: #> iptables -L -v Chain INPUT (policy ACCEPT 20 packets, 1190 bytes) pkts bytes target prot opt in ...
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iptables do not block all traffic i want to mysql port

Need to block all incoming traffic to port 3306 but two ranges. The thing is I can connect from other ranges anyway!. Think my drop rule is ok. Why is this? ]# iptables-save # Generated by ...
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Port bridge with iptables

is there a way to achieve the same thing than bidirectional socat functionality with nc mkfifo backpipe nc localhost 42042 0<backpipe | nc localhost 1042 1>backpipe But only by using iptables ...
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63 views

Make application use specific network interface

I have an openvpn connection and I need it to work only for one application, this app uses an specific local port. I used route-nopull on my openvpn config file and then: ip route add default via ...
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24 views

Filtered port with virtual server setup on a NAT

I have a Symphony SY602 ADSL router and I want configure a dynamic DNS to access my system remotely. I made a NAT virtual server in routers configuration and this is what I configured: Server Name ...
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1answer
33 views

enable internet on openvpn tun - azure linux

I am trying to do this with OpenVPN TUN on an Azure Linux instance: -=Android Client=- --> -=VPS=- --> -=Internet=- Client connects but no internet access. Iptables commands iptables -t nat ...
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Linux: Can user applications generate icmp messages?

I am using TOR and setting up a transparant proxy depending on users. I had trouble to constrain ICMP messages on UID. But I found an explanation for that on server fault. For the sake of privacy: is ...
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Why does iptables port aliasing work with only a single rule?

I have a service running on a particular port, but in order to make it accessible via a more memorable port as well as the normal port, I added an iptables rule that acts as a port alias: iptables -A ...
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Open firewall port on Mac OS X

I need to open port 8181 on my Mac OS X. On Linux, I would do: iptables -t filter -A INPUT -p tcp --dport 1664 -j ACCEPT iptables -t filter -A OUTPUT -p tcp --dport 1664 -j ACCEPT How do I do this ...
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18 views

Can't connect to Monet DB hosted in RHEL5

I'm not a sysadmin, much less a RHEL sysadmin, but for some reason I have to make a few config changes in a couple RHEL servers. I have to set up a couple services in different RHEL servers and they ...
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37 views

How can I configure one of the ubuntu desktops as “dhcp-relay-agent”?

How can I relay DHCP requests from LAN to WAN in linux so that the desktop connected to the LAN interface can have Internet access from WAN? Note: WAN has Internet access.
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MASQUERADING a veth

I want to bind an application to a wifi interface that might loose connection and receive a new DHCPed IP on reconnect. The problem is that the application can only be binded to an IP address and not ...