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 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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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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170 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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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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483 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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1k 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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164 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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133 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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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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62 views

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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93 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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830 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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48 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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143 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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100 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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606 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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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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170 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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666 views

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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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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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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706 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 {P-...
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130 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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367 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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117 views

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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56 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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211 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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Route all packets on port 80 from inside a vm to kali linux on another vm

I'm trying to route all packets on port 80 to kali linux so that I can ssl strip them but I cannot see to setup the iptables correctly to force all the packets to go to my other Vm. [ Virtual Machine ...
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352 views

iptables on debian blocking git pull, http api requests etc

I am using IPTables on an API server to block all incoming traffic except for SSH, HTTP and HTTPS. I need to have full access on the loopback interface to run beanstalkd amongst other things, and need ...
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672 views

How to force Google safesearch on entire network

I've a problem filtering web searches on Google domains. Currently I've a linux openVPN Server running with openDNS "family block". I can block a lot of websites with dangerous content and it's ok. ...
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120 views

Why my iptables configuration for port-knocking does not work?

I implemented the following iptables rules on my test server for a course. The firewall shuts down and I cannot access port 22. However, after knocking on the ports 1111, 2222 and 3333 in that order - ...
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11k views

OpenVPN won't connect from remote location

I set up OpenVPN on a linux machine in my basement. I'm able to connect from my Windows 8.1 machine without an issue when I'm connected to the local network. In this instance, I set the config file ...
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iptable definitions for routing and defence

I'm attempting to configure a firewall on my laptop that allows for routing. The main trick is, I don't want to allow for connections to be made that do not fall under the ESTABLISHED,RELATED ...
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104 views

Trying to configure iptables on Slackware 10

I am trying to configure iptables on a Slackware 10 machine. This Slackware version is required in my class - so I cannot upgrade it. After compiling it, I want to configure iptables - however, it ...
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429 views

Conntrack gets incorrect forwarding rules for outgoing protocol 41

I'm trying to forward protocol 41 (ipv6-in-ipv4) for an HE tunnel through a WRT54G running Tomato 1.28. Tomato 1.28 is running a 2.4 kernel that knows absolutely nothing about protocol 41, except that ...
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477 views

allow incoming ssh with openvpn client

I have set up an OpenVPN client on my home router. The moment the tunnel goes up, I can no longer ping my router from the internet using its WAN_IP. I would like to allow certain incoming connections (...
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1answer
247 views

Using IPtables to redirect IP address range to port range

I'm trying to set up an IPtables rule that will forward all packets to a /22 range to a single IP and port for debugging purposes. Based on the question here Using iptables to redirect ip address I ...
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How can I efficiently filter Dos packets? [duplicate]

I have recently been the victim of some Dos attacks. The facts : I received a very high amount of packets saturating my connection and preventing me from accessing the Internet during one hour (...
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295 views

Iptables to forward HTTPS traffic to remote HTTPS proxy

My goal is to use Iptables to take all traffic going to my server on port 443 and forward it to a remote HTTPS proxy server. So basically if I was to use my ip of 192.168.1.142:443 as a SSL proxy it ...
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50 views

Special type of DMZ?

So I have a standard modem-router setup all great to go, my Modem gives an IP Address from my provider via DHCP according to my Mac address. All is good. However, I now want to expose a new virtual ...
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Set block time with iptables

I have the following rules in ufw, for iptables: -A ufw-user-input -p tcp --dport 80 -m state --state NEW -m recent --set -A ufw-user-input -p tcp --dport 80 -m state --state NEW -m recent --update --...
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254 views

Will an inbound iptables rule in ddwrt on port 443 break https?

I want to run a vnc repeater service on my home ddwrt router. Due to the possibility of friends/family asking for support in unknown network environments, I'd like the host-repeater application to run ...
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104 views

No internet through OpenVPN

I am having trouble with my OpenVPN setup. I have a Linode box with an OpenVPN server installed on it and I managed to get Tunnelblick to establish a vpn connection from my mac. I followed this guide ...
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7k views

IPTables module ip_tables not found for root

We got a custom build Linux distribution from a vendor, which is not shipped with iptables enabled. root@xxxx:~# iptables -L modprobe: FATAL: Module ip_tables not found. iptables v1.4.21: can't ...
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368 views

Access lxc container services from other lxc containers via host

I've got a laptop with Ubuntu 14 Desktop. The laptop has WLAN connection to my LAN and is managed by network manager. Of cause, the laptop a nic (eth0), too, but it is not connected. I use this laptop ...