Iptables is used to set up, maintain, and inspect the tables of IP packet filter rules in the Linux kernel.

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Ubuntu on vagrant and iptables

I have an ubuntu desktop 14.04 running on a vagrant VM (virtualbox). I am trying to forward port 25 to port 2525 and I have executed the following commands: sudo sysctl net.ipv4.ip_forward=1 sudo ...
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13 views

GUFW limit access to websites

Do anyone know how I can limit access to certain websites during specific hours of the day using GUFW? If GUFW do not have this ability, what can I use instead to achieve this function?
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11 views

System Wide Proxy Setup - Must Or Optional

I would like to understand few things about system wide proxy on ubuntu. When a system wide proxy is set from network settings, does all applications (regardless from user) use this proxy or can ...
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25 views

Firewall with ability to block manually temorarily ip addresses, ports?

I have made a DDoS detection system that gives me info about malicious IP addresses and ports need to be blocked. Does anyone knows good solution of firewall, allowing me to do that. More automated ...
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9 views

Route traffic over different interfaces dependant on port

I have a problem I've been trying to tackle for a month now and just cannot figure it out. I've read every guide and tutorial I can find and tried all the solutions, they almost work but not quite. ...
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1answer
26 views

How to configure simple routing between NICs

I have the following setup: Physical router Internet interface 192.168.1.1 Port forwarding of IP 1194/udp to virtual machine below Virtual machine (VM) Ubuntu 14.04.3 Server AMD64 One virtual ...
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1answer
26 views

IP tables as a basic proxy not functioning as expected

I'm trying to accomplish simple packet forwarding on an Ubuntu 14.04 server (IP=192.168.36.217) using iptables. I want to take incoming packets destined to the server on a particular port and rewrite ...
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1answer
53 views

How to block facebook

I want to try blocking facebook on my machine. I started using /etc/hosts but that doesn't catch all subdomains, so I did some research and found this (and many similar solutions) which lead to this ...
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1answer
48 views

Iptables rules slow down loggining in via SSH

I am trying to build some basic iptables rules for my VDS: iptables -A INPUT -p tcp --dport ssh -j ACCEPT iptables -A INPUT -p tcp --dport 80 -j ACCEPT iptables -A INPUT -p tcp --dport 443 -j ACCEPT ...
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16 views

How to stop Ad-hoc from adding iptable rules when turned on each time?

In Ubuntu, iptable rules are added when Ad-hoc turned on each time for DHCP, DNS and packets forwarding. I know it's convenience and useful, but I've added my own iptable rules for those purposes. ...
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24 views

VNC Server Missing and UFW disabled and iptables empty after update?

I have an Ubuntu 12.04 computer in the other room that I remote into using Remmina Remote Desktop Client and VNC on another Ubuntu 12.04 desktop. It worked about 1 month ago. Now Remmina hangs at ...
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82 views

IPTables: Block incoming traffic connection to your IP address of your virtual machine

Host OS: Ubuntu 14.04 Guest OS: Ubuntu 14.04 (Virtual Box) I want to block incoming traffic connection from Virtual machine with IPTables. I have searched, One solution I found is static IP for ...
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26 views

iptables for setting up a transparent proxy

I have set up ubuntu server 14.04 on VirtualBox with two network interfaces. auto eth0 iface eth0 inet static address 192.168.1.5 netmask 255.255.255.0 gateway 192.168.1.1 ...
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14 views

Bluetooth connect changes iptables behaviour

I have a very strange situation where a bluetooth connection seems to change the behavior of the iptables firewall. Let met start from the beginning: I have a Onkyo stereo amplifier with a bluetooth ...
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1answer
18 views

Install Iptables server

I'm new in Linux and I don't know what it refers with Support but I can type some commands like ls, cd, sudo apt-get it always shows up command not found. So, please someone can help me?terminal
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37 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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24 views

Knockd not recognizing knocked ports Ubuntu Server

I've got a server with knockd running. When ports 7000, 8000, and 9000 are hit, knockd is supposed to insert a rule into my iptables firewall and allow the connection to reach a port (22). For some ...
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1answer
23 views

Can't connect to my ubuntu box outside my local network (VPN)

I have an Ubuntu 14.04 server running some services on different ports. I used to be able to connect to it (via SSH, samba, and a couple web servers on different ports) using a VPN. I'll use ssh as ...
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2answers
55 views

Confiruration DNAT in iptables

I have 2 PC be created by VMWARE 1. PC1 (make iptables router): ens33 's IP: 192.168.1.5/24 (network connection is bridged) ens37 's IP: 192.168.2.2/24. (network connection is wmnet9) 2. PC2 ...
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1answer
146 views

IPtables Config to Passthrough Internet 16.04

I am struggling to finish the config on my Ubuntu 16.04 fileserver to pass on the internet connection to my HTPC. See the network layout below: [Internet] <--> [DHCP Router] <--> ...
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204 views

Ubuntu 16.04 Tor Transparent Proxy

I want to setup an Ubuntu Server 16.04 to act as a transparent proxy for all traffic from a specific subnet to Tor. To be specific, I want all traffic on a subnet 10.20.0.0/16 when using the Ubuntu ...
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15 views

Zenmap Showing Filtered for iptables REJECT Rule

I've been recently messing around on my VMWare Ubuntu 15.10, and decided to test out my iptables and see if my Zenmap on my Windows host machine would recognize the ports being blocked. However, when ...
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43 views

How do I permanently removing a ban stored by Fail2Ban

I have two filters that have banned local addresses. I have added the addresses to ignoreip but the damage was done already and the bans are in place. Every time I reboot my computer I have to do an ...
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1answer
152 views

UFW not working in 16.04 server. Refers to earlier kernel module?

I am trying to move our mail server based on 12.04 to a brand new installation of 16.04 server. When I run sudo ufw status, I get: ERROR: problem running iptables: modprobe: ERROR: ...
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18 views

Deny guest user access to the Internet except to one address

I guess that an AppArmor profile has to be edited to archive that, but I'm lost on how to do it. If it is possible through an ufw or iptables rule I would be happy as well. Don't forget that it's ...
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52 views

Issues With Iptables

I have problems while performing iptables operations. modprobe: ERROR: ../libkmod/libkmod.c:556 kmod_search_moddep() could not open moddep file '/lib/modules/3.13.0-85-generic/modules.dep.bin' ...
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1answer
17 views

What is the UH flag in routing table

I'm using an Ubuntu machine as a server and it has two network interfaces. One is the 10.10.10.0/ 24 range and the other is 192.168.0.0 /24 range. I was trying to bridge these network interfaces as ...
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25 views

OpenVPN Ubuntu Server Routing Problems No Internet

I'm running OpenVPN on Ubuntu 15.04. When I connect to the server, I can connect and authenticate correctly (I use PAM auth because I'm lazy). Once connected I can't ping the server or access the ...
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2answers
42 views

Understand the differences between two network configurations for MAAS

I am trying to understand the differences between two network configurations for MAAS. My understanding is that the both achieve the same tasks where the first network connects to the internet and the ...
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1answer
32 views

Block port on one network address

I'd like to block a series of ports (mailserver) for all the network addresses on my server except one. I've got a server running Ubuntu 14.04.4 and configured with 2 ipv4 addresses per Linode's ...
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9 views

Port Access through VPN

I'm trying to access a PC from behind a VPN (PIA) using the Network Mgr on Ubuntu 14.04.4 but having some issues. Without the VPN up, I can access WANIP:8022 which port forwards to 192.168.1.10:22, ...
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34 views

iptables is blocking only some connections to port 80

I'm running a Ubuntu 15.10 server with an nginx webserver on it. I've used the following iptables configuration to allow port 80 and port 443 connections: *filter # Allow all loopback (lo0) traffic ...
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48 views

Adding VPN to firewall UFW

I'm having trouble at work in connecting to the work VPN while Firewall (UFW) is active. When i disable it "sudo ufw disable", there are no problems. When it's on, when trying to connect I receive ...
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45 views

open wifi Captive portal w/only local net (no internet/wan)?

I am trying to set up a wireless 'test' box to use on a private club (11,000 acres). The initial tests won't need anything fancy, it will just be checking the visibility of a hotspot from a high-point ...
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1answer
29 views

iptables-persistent / netfilter-persistent has (dependancy?) problem on 15.1

I'm trying to install 15.1 x64 on a new VPS. The first thing I do is ssh in and define a few iptables rules to drop non-ssh traffic, and now want to make those rules persistent. So: root@server:~# ...
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30 views

Easiest way to forward a port on local network

I have a server (python -m http.server) running on hostA:8000. Say I want to forward traffic from hostB:8004 to hostA:8000 How can I achieve that from hostB? I've already tried, $ sudo ufw allow ...
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49 views

Using UFW with ipsets

I am running Ubuntu 14.04 on a VPS for business purposes. The firewall is setup using ufw; testing reveals that it's working well. I'd like to further secure my server using techniques described ...
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27 views

Allow winscp/filezilla through iptables and fail2ban

I just launched a website within my school community and woke up this morning to logs of someone trying to bruteforce into my server. I followed some guides on digitalocean to set up fail2ban and ...
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29 views

Ubuntu is not accessible from LAN when ppp0 is up

I have successfully connected my Ubuntu server to a VPN server. Unfortunately, it is no longer accessible from inside of my LAN unless I kill the VPN connection. I use PPTP. What if I want a specific ...
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1answer
65 views

External access to Ubuntu single-node openstack horizon dashboard

I successfully installed openstack on spare server using the ubuntu single-node installer script. The openstack status page on the underlying ubuntu instance is green across the board. From the host ...
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1answer
52 views

Inherited Ubuntu server will not PING: What am I missing?

Update: It turns out, our in-house network suppresses pings. I demonstrated this by turning my phone into a hot-spot (thus changing my outbound gateway), connecting with a laptop, then pinging the ...
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56 views

Setting up NAT forwarding using iptables on ubuntu server 14.04

I have a server with 2 ethernet interfaces(em1 and em2). em1 is the internet facing interface(192.168.16.113) and em2 has a static address(10.1.1.100) connected to a switch. I have configured the ...
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10 views

How to route external traffic via mobile-phone usb modem and use ethernet for internal traffic?

Suppose my internal traffic all goes through some ip like 10.0.0.1 for example. I want to tether internet connection from my mobile phone to my desktop while still have the access to internal network. ...
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34 views

VPN doesnt ping the local network

I am using OpenVPN for connecting to office network. I have a VPN client configured on the laptop in my home Internet connection. The objective is to get connected to a VOICE SERVER sitting in the ...
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0answers
45 views

15.10 “falls off network” but all services are still up

A problem has been plaguing my Ubuntu 15.10 4.2.0-34-generic i686 VPS for a couple of weeks now. There will be a small (2-3Mb/s) spike in outgoing network traffic, and then the VPS will cease to ...
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53 views

IPTABLES Block FXP download from a IP

I am trying to block an FXP upload from a specific IP eg. 188.145.11.10. The problem is that I want to allow a download to 188.145.11.10 but I want to BLOCK the upload from that IP. For example: ...
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27 views

How to perform NAT with inside interface as bridge

I have a following network diagram: network diagram 192.168.0.0/24 network with 4 web servers (.1,.2,.3,.4). There are 2 Ubuntu 14.04 (VM1 and VM2) in it. They have 2 physical interfaces both (eth0 ...
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1answer
88 views

iptables and hacker prevention

Hello fellow Ubuntuers! here is an example of my iptables.rules file: *filter :INPUT ACCEPT [0:0] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [0:0] :f2b-sshd - [0:0] :f2b-sshd-ddos - [0:0] -A INPUT -p tcp ...
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1answer
56 views

fail2ban won't work

A few days ago I setup a new whole Server (Mailserver with Zarafa / Postfix, Apache, MySQL, and so on). Everything works fine.. except fail2ban. Fail2ban do nothing. He don't even act if something is ...
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1answer
304 views

Can't initialize iptables table `filter': Table does not exist (do you need to insmod?)

I'm trying to open up port 1900 for UDP in order for the Echo to be able to discover the HA Bridge using the following command but I get errors. What is the best solution to fix this? ...