iptables is the userspace command line program used to configure the Linux 2.4.x and 2.6.x IPv4 packet filtering ruleset. It is targeted towards system administrators. Please, when asking a question about iptables, add the output from the following command: iptables -L -v -n

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59 views

IPTABLES - Prerouting Issue - Port 443

I have a NAT server setup with 4 servers behind it. I have a PREROUTING entry to allow https/443 INTO my environment, specifically to to a web server running IIS on port 443. This works fine. ...
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17 views

minimalistic way of redirecting http/s traffic

In my scenario, I dynamically provisioning compute nodes to preform a task - in this scenario, a client is given the IP of the node to access using a specific application that access the application ...
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24 views

Route/Forward specific traffic to Interface

I want to use a Rasperry Pi as (Wlan-)Router. The Access Point is working so far: I have an Accesspoint with wlan0 (ip 10.10.0.0/255.255.0.0) and wlan1 connected to the internet. Now I want to route ...
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38 views

Docker is only listening locally on a container connected to a VPN

I've just nuked my CoreOS box and am rebuilding the setup as a Ubuntu Xenial (16.04) based docker platform. I'm happy with it so far but I'm now having to re-resolve a problem I already fixed on ...
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11 views

iptables rules only work using -m owner

Let's say I have the following rules, since I only want to allow traffic going over my tun0 interface: iptables -A OUTPUT -o tun0 -j ACCEPT iptables -A OUTPUT -j REJECT Unfortunately, the above ...
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42 views

How to create an iptables rule for a specific bonded network interface?

I have a "bare metal" server with a popular cloud hosting provider. (Running Ubuntu 14 in case that's important.) This machine has a network interface that faces the public internet, and also ...
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25 views

Multiple IP failover on VPN PPTP

I have a server at SoYouStart, I ordered an IP failover. I want to setup a PPTP VPN so I could be able to have one connection to the "normal" IP and one to the failover IP I couldn't manage to do ...
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37 views

Configuration SNAT iptables in ubuntu

I have 2 PC be created by VMWARE 1. PC1 (make iptables router): eth0 's IP: 192.168.1.4/24 (network connection is bridged) eth1 's IP: 192.168.2.2/24. (network connection is wmnet9) 2. PC2: ...
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12 views

How do I get default LXC iptable rules into Shorewall?

I'm setting up a server which will be hosting multiple LXC containers. However, starting Shorewall results in loss network access from within the LXC containers. If I reboot the LXC host and leaves ...
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84 views

Forwarding UPnP, DLNA traffic via computer to server

I'm about to tear out what is left of my hair with this. I was able to finally see traffic coming through, but not working in full, when using socat but this setup is not ideal. The idea: I have a ...
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24 views

How can i measure maximum connection, throughput on iptables?

As the title, I have a linux firewall as router. How can I measure maximum connection, throughput on my server? Thanks
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34 views

iptables, ufw, and psad - scanned UDP port alerts from router and devices on home network

I have a fresh install of Ubuntu 16.04. I configured iptables, ufw (with gufw), and psad using instructions from https://www.thefanclub.co.za/how-to/how-secure-ubuntu-1604-lts-server-part-1-basics and ...
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91 views

OpenVPN DNS resolution not working

I'm currently trying to get a simple OpenVPN setup working and I'm almost there, except for a DNS (or routing) issue I seem to be having. The client connects to the server just fine, and I can ping ...
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120 views

iptables: Redirect traffic from destination IP to new IP

I have a PC client. I like to redirect outgoing TCP connections on port 80 with the target IP 1.1.1.1 to the target IP 2.2.2.2. The full connection should be redirected, which means also the answer ...
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119 views

Debian iptables load fail

I Have Debian 8 Jessie and I have installed iptables, but it's not correctly. I can add rule just like: iptables -A OUTPUT -s 212.50.128.0/19 -j DROP but it's not working. iptables -L command works ...
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14 views

From what file/script libvirt inject rules in iptables when I start service libvirtd?

Everybody know that libvirt have his own list of rules for iptables, that he automatically inject in our iptables, after we start service libvirtd Problem: After standard installation of KVM and ...
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42 views

Forward port 80 to 8080 for a specific IP on the network

I have a specific PC on my network running a web service on port 8080. I also have a different machine which acts as a gateway/router, which I configure using iptables rules. What I want to do is ...
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46 views

Prerouting with iptables, destination port to DHCP ip

I have an iptables rule that translates requests to the same IP from different internal hosts by changing the source port. iptables -t NAT -A POSTROUTING -p TCP -d 173.32.1.2 --dport 873 \ -m state --...
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29 views

Can access server via SSH/FTP but other protocols won't work

I followed this guide to setup an "Upside-Down Ternet." Everything was fine up until the part where I configured IPTABLES then I lost SSH connection. Now I expected that because I'm messing with ...
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29 views

KVM - libvirt qemu script make duplicates in iptables

OS: CentOS 7 Firewall: iptables libvirt: 1.2.17 Problem: I used guide to make port forwarding from host to gues machines. Link to guide: http://wiki.libvirt.org/page/Networking#...
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30 views

netfilter, block port range [31000-32000] on public interface eth2

I need to block the port range [31000-32000] on my public interface eth2. Services can be accessed using private network interface eth3 I have tried : root@master-sbg-01:~/# iptables -A INPUT -i ...
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35 views

How to isolate two containers connected to the same bridge?

I have several LXD containers which are bound to a single bridge (the default lxdbr0 or another one, it does not matter). The host itself has another two interfaces, one ultimately connecting it to ...
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19 views

Iptables linux routing with 2 chain proxies

Im trying to setup a connection between a PCs in my local network, to foreign resource XYZ in a specific way. My network is currently configured like this: I have a pc behind the proxies -> Then I ...
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239 views

CentOS 5.11 apf/iptables; iptables sometimes fails when apf restarts

On one of our old servers, a CentOS 5.11 machine using apf as a front end for iptables, we're having an intermittent problem with iptables failing when apf restarts on occasion. When this happens, the ...
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60 views

Route all the trafic using iptables nat in linux

I'd like to route all the trafic through iptables NAT in linux, I'd like to route all the traffic through TOR. My script is accepting only TCP and UDP protocols, but I need to route all the protocols ...
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242 views

IPTables - Redirect ppp0 traffic to external side eth0

I've some servers on 2 differents networks. On the first network ( many servers ), I've only one public IP adress (ex: 193.193.192.192) and a small local network ( 172.16.1.0/24 ) ; On the second ...
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46 views

`systemctl restart iptables` blocks everything

Was connecting through ssh to a Fedora 23 server and decided to restart iptables after adding a new rule: systemctl restart iptables. However the iptables never restarted, or was very slow to restart (...
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28 views

multi gre tunnels to one IP

I have an issue with GRE tunnels after connecting multi-GRE tunnels with different IP's to the server, using this tutorial: http://wiki.buyvm.net/doku.php/gre_tunnel every GRE tunnel has interface ...
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19 views

DNS seems broken after iptables -t nat -A POSTROUTING -j SNAT --to-source SERVERIP -o eth+

During the setup of a L2PD VPN in Ubuntu 14.04, this line is entered iptables -t nat -A POSTROUTING -j SNAT --to-source PUBLIC_IP -o eth+ and then all the domains cannot be resolved in this ...
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53 views

vpn-over-ssh ipv6 tunnel getting permission denied connecting to tcp

Using my script, I can establish a working vpn for ipv4 and even able to ping ipv6 addresses. However, trying to connect to an ipv6 address I get "permission denied". ➜ ping -6 ipv6.google.com -c1 ...
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38 views

iptables change source and destination ports

I would like to receive traffic on multiple UDP ports and also my application (which is listening on a single port) to know from which port the request came from. If the source port becomes the ...
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12 views

Capture no-modified packet with iptables

I have a user-space program in which I process packets. I send them there with help of iptables. The problem is that I capture not original packet but modified. I have wlan0 interface up with access ...
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68 views

Traffic on eth0 despite denying it with iptables

Despite having an iptables ruleset which should not allow it - DHCP is working on eth0. Given the below information can anyone give me an idea of why? tap0 is not up (not that it should make any ...
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25 views

haproxy, iptables & iproute2 as a mean to select a different src vIP for same default GW

Got a HAproxy 2 node cluster/setup, each node has an external and internal NIC. External has a default gw: .249 service service pool A pool B srv1..srvN srv1..srvM ...
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30 views

firewalld multiple public ips to multiple private ips routing

I'm trying to use CentOS 7 server as a firewall/nat for some sensitive servers on the LAN. The CentOS server has multiple public IPs (one per box on the LAN) and I'm trying to associate each external ...
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35 views

OpenVPN connect to OpenVPN client network

OpenVPN Server Ubuntu 14.04 In Digital Ocean (Public and Private interface) OpenVPN client Ubuntu 14.04 I can't SSH from Server to client via VPN connection. Ping works fine. Tunnel is up. Followed ...
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26 views

Redirection of ports does not work

I have a VPS, and by some reasons common ports (1 - 1000) are closed. I installed iRedMail, but did not find any ways to change smtp submission ports, so I decided to just forward connection. I have ...
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32 views

Ldap server cannot accept Public IP

I have this LDAP server and 10 clients in the network. 2 clints can connect to server using server's private ip (10.10.10.10), but the other clients cannot ping private ip, so they use public ip ...
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55 views

iptables: still all ports open even if access had been restricted

Server: Debian 8.0 iptables v1.4.21 Scenario: I restricted access for aliens to all ports except 80/433. But aliens still can see all ports as "Open" when they use port scanner. But they can't use ...
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91 views

Squid - Forward Port 80 to SquidServer:3128

I have a -squid ProxyServer (Hostname: SquidProxy - 10.160.54.1 SM /16) -and a Client (Client1 10.160.55.1 SM /16) At the Client i have configured the proxy in /etc/sysconfig/proxy with the ...
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40 views

CentO7 multiple TCP port forwarding entries, does not allow certain ports

I have CentOS7 KVM setup that is using TCP port forwarding to forward SSH sessions to three guests running behind a NAT virtual bridge. This is the setup i'm looking establish 2020 -> 192.168....
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50 views

iptables (nth) load balance, connect failed: Connection refused when many request

I try to use iptables as load-balancer using round robin scheduling. Block Diagram My itables configuration on 172.18.3.190 like this : *nat :PREROUTING ACCEPT [42:7044] :INPUT ACCEPT [26:4290] :...
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41 views

What rules do i need to allow ipsec in iptables firewall?

I have a server sitting on a private subnet behind a iptables firewall. On that server I am planning to create site to site VPN to Amazon VPN. I am not sure what rules do I need to put in my iptables ...
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68 views

StrongSwan IPsec and NAT

I have an IPSec tunnel to the network of our customer running on a Linux box with StrongSwan. On there I have to do source NAT to translate our network addresses to the subnet they assigned us. This ...
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46 views

ISP provides 400MB connection but behind iptables firewall I only get about 150MB

I have COX communications as my ISP and I have a 400 MB connection at work. I have had for years an iptables firewall I setup that runs great. CPU Info Intel® Core™ i5-2400 Processor (6M Cache, 3.10 ...
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23 views

DNS using GRE work 50%

l'm in a big issue here to make it work I'm already at least about 60% done, but it is difficult and I would like to count on the help guys here who may have already done this type of configuration. ...
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66 views

Run node server on port 8080, use iptables to redirect traffic

I saw in several venues that in order to run node as a user, and yet get it to listen to port 80, you can do a simple IPTables trick: sudo iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 80 -j ...
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18 views

IPTables debugging

I've got a weird problem. I've got a primary host in Nevada and a satellite site in Maryland. They both use the 192.168.21.0/24 subnet (as well as .18.0 and .101.0) and have some overlapping addresses....
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29 views

Port forwarding with different gateway

Here is my current setup: Public IP -> Iptables firewall_A with DNAT from Public IP to -> mail server Iptables rule: iptables -t nat -A PREROUTING -d PUB.LIC.IP.ADD -p tcp --dport 25 -j DNAT -...
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22 views

How to correctly configure iptables block output (wordpress)

I just cleaned my WordPress installation after attack. They used my server to attack other sites. I've cleaned everything but I want to use iptables to block outgoing requests from my server. I ...