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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38 views

Iptables seems to be blocking outgoing HTTP connections

We recently noticed that outgoing HTTP traffic seems be blocked. Specifically we need to allow HTTP requests to a give website URL. I'm not sure if this is possible as I believe typically it must be ...
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0answers
20 views

iptables: Allowing connections initiated from inside

My debian squeeze servers (not in a state to upgrade) are currently using the following rule to allow the connections that are initiated from the same server and later connected to random ports from ...
0
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2answers
226 views

Redirecting port 8080 to port 80 - how to add in /etc/sysconfig/iptables file?

On CentOS 7 Linux (acting as LAMP - and not "firewall/gateway") I have created a custom systemd service for running embedded Jetty at port 8080 as user nobody: [Unit] Description=WebSocket Handler ...
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0answers
24 views

How to forward port through VPN on Linux

I'm setting up a small CTF (hacker competition) and have a machine that hosts VMs. One of these VMs will be the target. The host machine cannot be reached through the internet, so I have set up a ...
1
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0answers
31 views

NO routing in VPN to client side

I try to configure the following network structure in one dev VMWare environment. W.XP------| |-----W10 192.168.5.100 | | 192.168.4.100 ...
2
votes
0answers
28 views

Iptables u32 matching nat

I'm currently setting up IPtables to redirect certain UDP payloads to my application. Here is an example of what I have working so far: iptables -t nat -I PREROUTING -p udp -d {IPDST} --dport 27055 -...
1
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0answers
41 views

policy routing for local outcoming connections

I have a multihomed setup with two upstream providers. And I want to confine some connections to use only one provider — local outgoing connections that is. So, I've made a custom routing table, which ...
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0answers
24 views

VPN connection problems regarding plex media server and voice over IP [migrated]

I have a home server - running Debian Jessie and plex media server. My router (fritzbox) allows all smartphones in my LAN to receive incoming landline calls (due to a certain app). This part works ...
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0answers
40 views

How to do Multi WAN routing based on latency/distance to the target IP

I have two different internet connections available (DSL & LTE), and I'm building a router to "combine" those. What I would like to achieve: The routing should happen based on the latency or ...
1
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0answers
8 views

3 server point to point bridge loop

I have a setup with 3 servers (A, B and C) running debian jessie which are all directly connected to the other two servers, so it is a ring-like layout. I'd like them to only have ohne IP each like if ...
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0answers
38 views

blocking subnets in iptables

I currently have a router attached to the main network (192.168.0.x). On this router, I want the ethernet-ports to link to the main network, and the vlan's (wireless) to be set up via a separate DHCP ...
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1answer
33 views

Reloading IPTables Disable Access to Site

I have CentOS 7 VPS. IPtables contains 2000 IP block rules. When reloading it takes 80 seconds to complete reloading. During that 80 seconds, I notice that around 15 seconds, my site becomes ...
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0answers
51 views

Iptables firewall causing instability

I've made a script to set an iptables firewall,but it's Causing instability on the local network aplication . The firewall is droping the connection between the clients and the server for a while ...
2
votes
1answer
27 views

How do I add a mangle rule to my saved iptables firewall rules file?

I've set up OpenVPN on my Debian server and would like to add a rule to iptables. I already have a file that lists default filter rules that iptables reads from (pre-up). I tried adding the rule to ...
2
votes
0answers
45 views

IPTables DNAT Exemption

TL;DR - I'm looking for a way to send all my external traffic through a proxy server but not send all my internal traffic through a proxy server. How can I achieve this? My end goal is to forward ...
0
votes
2answers
52 views

iptables: How does DROP policy is working with custom chain

I've been working on iptables for a project. The iptables are implemented for different interfaces via custom rule chains. Due to the declaration of accepting rules the default policy for INPUT is set ...
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1answer
27 views

Need to limit INPUT PSH+ACK packets

I have several HEAD queries a week that look like this (I assume that this is some kind hack attempt): 289 24133.787750 81.94.192.233 -> 95.85.35.251 HTTP 118 HEAD / HTTP/1.1 290 24133.987861 81.94....
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votes
1answer
30 views

iptables port forwarding to server with different port

I am trying to port forward from one server to another. I have tried numerous iptables commands but they don't work. Am I doing something wrong? Here is my setup: VPS1: 1.1.1.1 SMTP Port : 25 UFW:...
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0answers
30 views

DMZ with 2 firewall - How to allow access to DMZ from LAN

i following tutorial to setup DMZ with 2 filewall. Diagram Network can be found here --[Modem]------eth0-[External FW]-eth1------eth1-[Internal FW]-eth2-------[Intranet] External FW: eth0: 192.168....
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0answers
12 views

L2TP and Openswan NAT

I have a connection between a local CentOS7 machine and a remote customer server connected via L2TP. I can communicate CentOS7 <--> Customer flawlessly, but the problem begins when I try to ...
0
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1answer
22 views

IPTables Policy INPUT DROP but accepts connection

I configured iptables with the following rules: iptables -I INPUT -p tcp --dport 22 -j ACCEPT iptables -P INPUT DROP iptables -A INPUT -p tcp --dport 80 -j ACCEPT iptables -A INPUT -p tcp --dport 443 ...
0
votes
1answer
22 views

allow ssh outgoing with iptables default policy as drop

Good day all My VPS allows incoming ssh connections as required (see rule), however attempting outgoing ssh connections fails to connect with $ ssh xyz.ddns.net ssh: connect to host xyz.ddns.net ...
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2answers
115 views

Linux change source ip adress of incoming traffic

I have a web service running on port X. It was never intended to run outside a local network, but I would like to access it over the internet. Therefore, I need to change the source IP address of all ...
0
votes
1answer
44 views

Wifi router block internal traffic

I make a wifi router from raspberry with raspbian. My eth0 connect to a network that can access internet, and I make a local network for client connected to my wifi. My wifi works as a gateway for ...
1
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0answers
31 views

TC not classifying packets correctly based on iptables MARK

I have machineA that is connected to the internet via eth0. MachineB on the other hand is connected to machineA through a mesh and is connected to the internet via machineA. I am trying to give lower ...
0
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1answer
35 views

IP Range - Subnet network configuration on CentOS 6.4

I have problems to configure an subnet /25 on an vps with CentOs 6.4 have tried different version. The original eth0 settings are: DEVICE=eth0 #HWADDR=de:8f:24:e9:7b:04 TYPE=Ethernet UUID=64e110dd-...
1
vote
1answer
34 views

Port forwarding prevents container from updating

I use the following route on my host machine in order to pass all my traffic to a NGINX server running at port 8080. -A PREROUTING -p tcp --dport 80 -j REDIRECT --to-port 8080 Unfortunately when I ...
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votes
2answers
440 views

ERROR: could not open directory /lib/modules/4.2.0-25-generic: No such file or directory

I upgraded Ubuntu 15.10 to 16.04 and somewhere there must happened my trouble. I firstly realised my trouble when I wanted to do sudo iptables -A INPUT -m state --state NEW -p tcp --dport 80 -j ...
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0answers
17 views

How can I forward blocked http/https traffic by IP Tables to another host?

I have a huge list of IP Addresses blocked by iptables with rules set to DROP all of their traffic. The main traffic that comes is either http (port 80) or https (port 443). Is there a way (without ...
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votes
1answer
24 views

Iptables in ubuntu 14.04 doesn't have statistics extension

I have an Ubuntu box and need to manage iptables rules with the help of statistics extension but everytime I try to run iptables -m statistics --help I'll get such error iptables v1.4.21: ...
1
vote
1answer
49 views

How to mangle IP addresses based on time using iptables

I want to change my IP addresses based on time not urls. Following is my iptable rule to mangle IPs I have : sudo iptables -t nat -A POSTROUTING -o em1 -p tcp --dport 80 -j SNAT \ --to ...
0
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1answer
27 views

Simultaneous outgoing connections limit with iptables not working

I run a website that technically acts as a proxy to another website (I make HTTP requests to it), and I needed to make sure not too many simultaneous connections were made, I thus limited it to 29 ...
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votes
2answers
37 views

Route only Web Traffic of my Ubuntu machine through OpenVPN proxy [closed]

My question is simple, but I couldn't find a clean, step_by_step guide/example on the Internet. I have an OpenVPN proxy server and I want to just route the web traffic of my local Ubuntu machine ...
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2answers
43 views

OpenVPN Variables Passed via Script

Can someone explain and/or direct me to a summary of the variables that are available to be passed to OpenVPN upon a client connection? For example, what do the following $1, $2, $3, $4 values ...
0
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0answers
23 views

Add Filters to Users

I am running OpenVPN on Ubuntu 14.04 (dev tun) and I can't seem to get my learn-address script to run below I would like to run the learn-address script each time a user connects to OpenVPN that ...
1
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0answers
18 views

iptable connetion to VPN Server (VPN + DNS)

i want to create iptable rules that allow no traffic to the outside world with the exception to my VPN - Server (xx.xx.xx.xx) and local Network 192.168.0.0/24 The rules i defined: iptables -F ...
0
votes
1answer
49 views

IPTABLES nat to LXD Containers

I created the following temporary rule that I enable occasionally but I would like to remove it without the need of restarting the machine. Can someone provide me the command? sudo iptables -t nat -...
0
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0answers
57 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. ...
0
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2answers
64 views

Is it safe to open all UDP ports range?

I've setted some main ports - 20, 21, 22, 23, 53, 80, 443 for incoming and outgoing TCP connections. If i want to connect from inside my server to another ftp server, it uses random UDP port in range ...
0
votes
0answers
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 ...
0
votes
1answer
34 views

IPTABLES blocking ports that should be open

I'm using centos7 and have the following rules set up: *filter :INPUT DROP [6:394] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [42:6917] -A INPUT -p tcp -m tcp --tcp-flags FIN,SYN,RST,PSH,ACK,URG NONE -j ...
1
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2answers
89 views

Access Point Iptable/Route rule for allowing device discovery? Devices can connect manually, but not automatically. Multicast/Upnp issue?

I setup a wireless access point on my server and for some reason, everything works but automatic discovery features. I can't see any other devices, upnp devives aren't discovered, and I think it's a ...
1
vote
2answers
45 views

iptables nat same port, multiple providers

my configuration: # ip route sh zzz.zzz.zzz.0/24 dev eth3 proto kernel scope link src zzz.zzz.zzz.1 yyy.yyy.yyy.0/24 dev eth1 proto kernel scope link src yyy.yyy.yyy.146 xxx.xxx.xx8.0/23 dev ...
1
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3answers
138 views

Forward traffic between VLANs with iptables

We're having the following 4 VLANs on my network, connected to an Ubuntu Linux box with DHCP. This Linux should act as the L3 router as well. VLAN 10 on interface eth1.10 with subnet 10.10.10.0/24 ...
1
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1answer
61 views

pacemaker virtual ip loadbalancing with clone and clusterip

I am trying to make a loadbalanced gateway for a group of natted machines. I have 3 centos nodes. Initially only one node was supposed to have the internal gateway ip and that works well. Traffic ...
0
votes
1answer
28 views

NFS mount internal error

I have a server that I use for NFS share. 4 servers use it without a problem. I configured a new server and that can't mount. I get this error mount.nfs: internal error In the logfile of the ...
0
votes
0answers
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 ...
0
votes
1answer
63 views

Multiple Gateways for Single Subnet

Right, this might be a long one, so bare with me... I have 2 machines, lets call them local1 and cloud1. local1 has 3 Nics: 2 connected directly to cable modems with public IPS (call them eth0 and ...
0
votes
1answer
23 views

Why is my ISP box talking to my DMZ host?

I have a setup where an internet connection is available via ISP box, which has a DMZ feature (one of the hosts can be exposed to Internet). The general setup is the following Internet - PublicIP - ...
0
votes
0answers
36 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 ...