iptables allow creation of rules to define packet filtering behavior.

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What is blocking: Firewall and tcpwrapper?

Is it possible to find whether firewall(Iptable) or tcpwrapper is blocking a connection without accessing the remote server? (tcpdump?) Thank you,
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32 views

Port forwarding with iptables and PIA VPN for single user

I've gotten a Private Internet Access VPN setup on a Mythbuntu 14.04 machine and I am at wits end trying to get port forwarding working with rTorrent (and ruTorrent). My setup is rTorrent running ...
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Fedora 21 Port Forwarding with firewalld (firewall-cmd); how does it REALLY work? Or, does it?

Fedora's ability to forward ports using the apparently "native" networking software, firewalld, appears to continue to be broken beyond credulity. Please note that it hasn't really worked since at ...
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29 views

Linux - iptables - get YouTube streaming bytes usage

How do I get bytes usage using iptables for a particular IP, including YouTube streaming videos? Currently, I am using the following IP tables rules to get data usage by IP address: sudo iptables -I ...
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IPtables errors

I am working on a project. I am trying to write iptables rules to control network traffic. I have written some rules. When I try to apply them to the boxes that I am working on I either get locked ...
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linux nat different rules

eth0 (192.168.1.0/24) --> wan eth2 (192.168.10.0/24) --> lan0 I use these rules to enable NAT on my linux gateway: iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE iptables -A FORWARD -i ...
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57 views

How can I redirect internet traffic from local to proxy server with ip tables (DEBIAN 6)

So i made topology as shown in figure. Router have 3 interfaces like this: eth0 to internet side (with ip 192.168.1.10/24 gateway 192.168.1.254/24). eth1 to server-PC side (with ip ...
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29 views

Route wireless LAN through OpenVPN

I am trying to set up my home server to act as an OpenVPN gateway so I can connect to my VPN from any device without installing special software of them. My server is running Ubuntu 14.04. The host ...
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13 views

How to route vpn traffic over hostapd-raspberry pi

I have a raspberry pi running hostapd and I am able to connect my laptop as a wifi client to the raspberry bi wifi router. The problem is with the vpn traffic, I cant connect to my office vpn with ...
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14 views

iptables drop policy

Audit my rules I'm ask if I really need of two INPUT policy: iptables -P INPUT ACCEPT iptables -F iptables -A INPUT -i lo -j ACCEPT iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT ...
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Why does my PPTP connection work if I DMZ the server behind the router, but it does work if I use port forwarding?

Why does my PPTP connection work if I DMZ the server behind the router, but it does not work if I use port forwarding for the wide area network? Is there another port I need to open/port forward ...
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32 views

iptables not getting saved ? centos

I am trying to save the iptables, when I run command #service iptables save it says [ok] but when I again open the iptables the rules get revert to default. Can anyone help me to understand this ...
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-m owner --uid-owner

Please point out to me if -m owner --uid-owner spring can be used in the following rules: (1) iptables -A OUTPUT -o lo -m owner --uid-owner spring -j ACCEPT (2) iptables -A OUTPUT -o eth0 -m ...
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26 views

How to forward range ports in my linux server?

Is there any tools to do range port forwarding in my CentOS system? Just like any ports from 8000 to 9000 shoud be forwarded another IP's 8000~9000 respectively. I know it's easy to be done in Router ...
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24 views

mount times out with iptables --policy OUTPUT DROP

I previously ACCEPTed all output traffic by default. Recently changed the policy to DENY output by default, only opening ports needed for server/application functionality. When I tried to mount a ...
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46 views

CentOS as home network router: IPTables Port Forwarding failure

I have currently set up a home server with a CentOS 6.6 installation on it. The server has two NIC interfaces which I'm using it as my router and DHCP server. Here's a diagram showing the network ...
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33 views

DDOS defence with iptables

I have server with Debian 6 with a many games servers and sadly, I'm getting ddosed. So, there is my ask for help. I want make solid firewall, where my server will safe.
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On a router, what decides if a packet should be forwarded or directed into the router itself?

I'm trying to learn how packet routing works on a linux-based router (OpenWRT in my case) a bit better for setting up a few projects/just-learning. Referencing the below chart, I'll break this into ...
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2answers
54 views

Is it possible to have multiple virtual machines with the same (guest) ip on the same host?

What I try to achieve: Multiple virtual machines (virtualbox) on a Debian host which communicate with another server (not with each other or the host). All VMs need to have the same static network ...
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CSF not blocking port when removed from csf.conf

I have removed VNC port 5901 from the csf.conf configuration file and executed a csf -f a csf -x and a csf -e to flush and restart CSF. There is a vncserver running on port 5901 and when doing an ...
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27 views

Does NAT allow accessing internal network (or router's local interface) from outisde by default?

I am using older SOHO router wl500gP (it is v1 but I think this is not important) with custom Oleg firmware. My topology looks like this: 192.168.3.3 192.168.3.2 NAT 192.168.2.1 ...
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44 views

iptables allow INPUT from a specific url

I'm using DD-WRT, and can telnet into it to add iptable rules. I'm looking for a rule that will allow IN from a specific address (say, mydomain.com) on port 80 that will point to an internal IP (say, ...
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how to automate creating firewall rules?

There is a complex live system - few vlans. In each of them there are linux servers, and on every server there are services. Services connect together - for example service http on host A connect to ...
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output in iptables

I have added the rule to iptables file, however the command does not show it. $ sudo less /etc/sysconfig/iptables Generated by iptables-save v1.4.7 on Fri Oct 24 13:28:48 2014 *filter :INPUT ...
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41 views

How to enable ping between machines connected in two interfaces?

I have a linux board with two ethernet interfaces as mentioned below. eth0 connected to another linux machine (ad-hoc) eth0 on board 191.168.1.2 connected to Linux machine 192.168.1.3 eth1 on board ...
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iptables | redirect from local [interface:port] to local [interface:port]

0 down vote favorite I have two interfaces eth0 (192.168.1.95) and eth0:1 (10.0.0.100) i want all packet for 192.168.1.95:9900 (from any 192.168/24) will be redirect/forward to 10.0.0.100:9900 and ...
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How to prevent an application from connecting to a network with iptables? [duplicate]

I have read the manual page of iptables in terminal, but it has complicated syntax and I don't fully understand how to use options like: user, user ID, UUID and so on. Suppose my username is foobar ...
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Shorewall configuration : providers and LAN

Hi all and thanks in advance for the answers. Currently, I have different providers configured in shorewall. I'll will probably have to change one of them. The problem is I won't have any Public IP ...
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Impossible to browse web after configuring iptables

I'm trying to configure iptables on my ubuntu computer. These are my rules: Chain INPUT (policy DROP) target prot opt source destination ACCEPT tcp -- anywhere ...
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1answer
37 views

Email evading my spam filter

I'm having trouble with email evading my Barracuda Spam firewall. I believe the spammers are using my A Record to bypass my MX Record which is what directs email to my Barracuda for processing. How ...
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44 views

Redirect user once using iptables

I have an access point (Raspberry Pi) running Raspbian (Debian). I need it to redirect user visiting specific website to another one, but only when the user visits the first site for the first time. I ...
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why do we have same chains in different tables of “iptables firewall” in linux?

why do we have same chains in different tables of "iptables firewall"? Like for example: we have "output" chain in filter table, nat table & mangle table.
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iptables and RETURN target

I don't understand what the RETURN target does in a iptables command. The doubt comes from this guide where it says: A chain is a set of rules that a packet is checked against sequentially. When ...
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iptables - hairpin NAT dual WAN

Here is my lab Client LAN: 192.168.150.95 Gateway: 192.168.150.1 RDP Server LAN: 192.168.150.2 Gateway: 192.168.150.1 Linux Router WAN: 177.129.XXX.XXX Gateway: 177.129.XXX.XXX LAN: 192.168.150.1 ...
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Where can I find what the latest iptables version is?

I may be blind but I just can't see what the iptables latest version is. I've checked iptables homepage. I've also searched the internet and nothing.
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34 views

Unable to ping/SSH web-facing server

I just installed Ubuntu 14.04 LTS onto a box that's set up with one local NIC and one web-facing NIC. The web-facing NIC is configured with a static IP per my ISP. Because networking and security ...
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unable to block out-going traffic

I've run $ iptables -I OUTPUT -j DROP -d [ip address] and found that some processes are still connecting the destination ip I've blocked above: $ lsof -p [pid] it shows: ...
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How do you tweak iptables limit rules on openSUSE Tumbleweed?

I have a fresh install of openSUSE Tumbleweed, it is logging a lot firewall related stuff due to my apple devices multicasting to enable airplay. Lines look like: Mar 14 12:45:13 server kernel: ...
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iptables for Asterisk

I am running Asterisk with FreePBX. I would like to log all failed attempts and after a while ban them. Ideally after 3 failed attempts in 1 minute, ban for 1 hour. Is it possible to see if this ...
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How iptables tables and chains are traversed

I know linux has 3 built-in tables and each of them has its own chains as follow: FILTER: PREROUTING, FORWARD, POSTROUTING NAT: PREROUTING, INPUT, OUTPUT, POSTROUTING MANGLE: PREROUTING, INPUT, ...
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Restrict the maximum number of independent IP connection on specific port at the same time

I set up a server as a socks5 proxy. I'd like restrict the maximum number(1 or 5 or 20) independent IP connection on specific port at the same time. I have searched on google, only see some articles ...
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109 views

monitor bandwidth on interface with tc or iptables

I would like to log a warning message to /var/log/messages file if either ingress or egress bandwidth on eth0 interface is over a certain threshold. I could do this with a script which reads the value ...
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61 views

Best way to transparently redirect traffic to proxy

I've implemented a wireless router using hostapd on Debian Wheezy running on a Banana-PI. To access the internet, this router is attached to another network that I haven't any control of via ethernet. ...
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2answers
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How to disable network access for a user?

Trying to disable the network access for the user: [root@notebook ~]# iptables -I OUTPUT -m owner --uid-owner tempuser -j DROP [root@notebook ~]# ip6tables -I OUTPUT -m owner --uid-owner tempuser -j ...
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failing to tunnel F5VPN through OpenVPN

summary I need to tunnel an F5VPN through an OpenVPN in order to ssh from a client device (Debian laptop) through a firewall. The OpenVPN works, but I lose all networking on the laptop once I start ...
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iptables-save return with errno 1 - operation not permited

When I run the command iptables-save it returns with errno 1 - opearation not permitted If I do: iptables -L and then: iptables-save then iptables-save succeeds This error happens only ...
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45 views

Redirect traffic through the server

My task is to redirect traffic (port range) through the server. Here is the schema: Why NAT is not appropriate here: If NAT is set to "Tunnel Server", then all users will be assigned the same IP. ...
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35 views

Config iptables ssh over VPN

How can I define a rule that only allows ssh via VPN in iptables? My iptable Rule is following: #!/bin/sh IPT="/sbin/iptables" $IPT --flush $IPT --delete-chain $IPT -P INPUT DROP $IPT -P FORWARD DROP ...
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58 views

Switching between Network Interfaces

I am trying to write script to switch between two interfaces on a Linux machine, wlan0 and eth0. My primary reference is: http://askubuntu.com/questions/338100/forwarding-traffic-between-2-interfaces ...
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25 views

Nat with saving real client IP

I have this schema: Client -> NAT server -> Game server On NAT server I have the following rules: iptables -A FORWARD -d $MC_IP -p tcp --dport 25550:25580 -j ACCEPT iptables -t nat -A PREROUTING -d ...