a technological barrier designed to prevent unauthorized or unwanted communications between computer networks or hosts

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Can you run a VPN connection over HTTP?

Is it possible to connect to a VPN Server having a tunnel over port 80, thus eliminating all the port blockings of a firewall?
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83 views

Why using (or not) dedicated bridges with LXD?

Question: Are there specific drawbacks of using a single bridge, as opposed to a dedicated one per container? Details: I have a host which runs a few LXD containers. I initially decided to have one ...
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38 views

Block IP beginning with, U.F.W

Someone is running a registration bot on my site and I have taken steps to prevent the registration, but now I want to block the whole IP range from even being able to access my site. I have set up ...
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30 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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1answer
66 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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22 views

torrent blocker for network

Does anybody know of a great torrent blocker which blocks all torrent traffic in a network. We are currently using untangle, which works great, but i was just wondering if there are maybe other good ...
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1answer
40 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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2answers
28 views

Network configuration | apt can't download anything

I'm having some issues with the FTP server I'm currently setting up for my company. I installed the server completly, updated everything and the server works fine now. I installed everything behind a ...
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1answer
52 views

How do I block Internet for an app using an apparmor custom profile?

I'm trying to block internet access for an app because it always asks for purchase or update even though it's free. I created an apparmor profile for that app and enforced it but after enforcing, the ...
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3answers
64 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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28 views

static arp with a wlan repeater

The scenario: when i activate static arp at my dhcp settings in pfsense i can't access pfsense itself. but when i deactivate static arp i have access to pfsense. then i found out with a wireshark ...
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84 views

Accessing a LAMP webserver that's behind a Ubuntu VM acting as a firewall

I currently have two VM's set up in the following manner: /-----------------------\ /-----------------\ | Ubuntu VM | /---------------\ ...
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31 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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1answer
73 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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44 views

Printing with UFW

I have just set up a print server using CUPS and Avahi to allow printing from iOS devices on my home server. I have UFW set up to block all traffic that isn't on my VPN or over LAN. I have even set up ...
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1answer
63 views

UFW rule doesn't work

At first enable the ufw status. root@sai:~# ufw status Status: active It blocks both incoming and outgoing connections, tested by using ping ssh from both sides not working. root@sai:~# ping 192....
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36 views

How to make ufw allow only connections from outside lan

I am setting up a server at home from an old pc with ubuntu, and would like to "separate" it from my local network by configuring the firewall to allow only connections from outside my lan. I found a ...
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31 views

How to block Internet access for some devices on given hours?

I have a Ubuntu machine (15.10) running as a gateway which routes / firewalls traffic between a LAN an Internet. I need to block Internet access during some hours for specific devices on the LAN. ...
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1answer
64 views

How to stop https warning of untangle captive portal?

How can stop https warning from displaying on webrowser if a client tries to connect through my network. The scenario is: As I have configured captive portal on untangle(it is a UTM) so if user tries ...
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25 views

Obfuscating a proxy

I've been using a server as a proxy, channeling my connection with SOCKS and/or sshuttle. Unfortunately, SSH to my server was recently blocked, PPTP is unreliable, usually failing to connect and ...
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1answer
111 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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0answers
99 views

Why does remote SSH connection time out?

My server runs Ubuntu Server 14.04. When connecting over SSH from a local LAN client it works fine. When I connect using a different machine from an outside network, I get 'connection timed out'. I ...
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1answer
99 views

Is port 5432 open for postgres?

Here is the output of the netstat command on ubuntu 14.04 server: admin@ibm-testbox:~$ netstat -tulnp | grep 5432 (No info could be read for "-p": geteuid()=1000 but you should be root.) tcp 0 ...
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34 views

Server iptables configuration

I have an application installed in the /usr/local/tomcat/fakebook directory. I want to allow any user to use the app and also all external user to use the app. I just want to allow connections to the ...
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72 views

UFW not opening port

Could someone explain why I can't open port 64738? I opened it with sudo ufw allow 64738 But when I test with nmap, the port is still closed. > sudo ufw status Status: active To ...
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39 views

Can't connect to external IP

My local IP is 192.168.1.2 I have multiple servers running including a web server. If I point my pc's browser to localhost:80, 127.0.0.1:80 or 192.168.1.2:80 it loads. If I point my android's ...
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1answer
79 views

Allow only a specific ip address to an open port

I have a Zimbra server and the admin port, 7071, is open to the world. I had someone try to get into it yesterday and that locked the account. I was wondering if I can block all access to this port ...
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18 views

Comodo and GUFW

Good morning to all. My question has to do with the use of GUFW for blocking traffic except the updates for Comodo for linux AV. I need a safe pc that will be used only for checking and cleaning usb ...
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1answer
37 views

How do you whitelist an IP address with just one line command?

I've been searching how to whitelist a IP address (ex. 123.123.321.1) with Ubuntu 12.04. But everyone seems to give long elaborate answers. Is there just 1 simple command to whitelist an IP address? I ...
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50 views

Still seeing connections from IP after blocking in fw

So I'm using iftop to monitor connections on my server, and I'm seeing this ip address 116.110.127.24 making constant connections on ssh port. (I'm not sure if this means 22 or my actual ssh port, it ...
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1answer
53 views

how can i kill all established connections before running iptables bash scrip

there is established connection from before running iptables bash script, and even this connection is blocked by iptables, but it keeps running because it is in established status, which according to ...
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5answers
583 views

ssh connection refused

Hi I'm having a problem with my ssh, which is magically stopped working and I couldn't figure out why. The message it give is: ssh: connect to host <host> port 22: Connection refused I don't ...
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81 views

UFW block 80 port? 14.04

Im using ubuntu 14.04.On ufw 80 , 80/tcp , 80/udp is allowed from all. But when i look to logs. its look like this *my server ip YYY.YYY.YYY.YYY *and i delete my mac and ip Feb 21 16:59:14 server ...
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1answer
79 views

How can I dynamically determine the IP mask to use for dynamic ranges?

I have a list of ranges for IP addresses that I want to block, the ranges are like 210.80.32.0 to 210.80.63.255 How can I dynamically determine the right 210.80.32.0/NUMBER to capture the full range? ...
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61 views

OpenSwan Configuration

I am trying to set up IPsec tunnel between two hosts. Host A has an IP 10.2.40.3 and Host B has an IP 10.2.60.4 Host A is connected to the router with its GW being: 10.2.40.4 Host B is connected to ...
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64 views

How to allow DHCP between 2 networks using Shorewall?

I have a server with hyper-v and 3 networks: eth0 is virtual, eth1 is physical, eth2 is extranet from ISP. Virtual network has a DHCP running and all virtual machines can reach it fine. But not the ...
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1answer
28 views

the packet flow from a network interface to a local process? help!

I'm read Linux Iptables Pocket Reference. So I do not understand the figures presented. It says that packets travel through chains, and are presented to the rules one at a time and in order. Then ...
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77 views

Configure Ubuntu 14.04.3 firewall for NAS TS-453A

With Qfinder I can manage my QNAP TS-453A from my Ubuntu 14.04.3 LTS laptop, only when the firewall in Ubuntu is disabled. As soon as the firewall is active, Qfinder and the NAS stop both and are not ...
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67 views

Recover Server from recovery mode(firewall closes ports)

My server( Ubuntu 14.04 - Plesk - RAID1 ) is now in normal mode. Almost all ports disabled by firewall as plesk port 8443, so plesk login panel is not opening. Also Website is not opening. ...
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1answer
140 views

apt-key add <file>; apt-get … keyserver timeout on same key

I'm behind a firewall (i have the proxy setup - just like in Why does add-apt-repository now fail to retrieve keys behind my proxy server, but I can update package lists and manually receive the keys?)...
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15 views

Output SSH in shorewall

I can not use ssh or scp where has installed shorewall, returns me the message: ssh: connect to host xxx Connection refused Which should add a rule to enable this feature?
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157 views

IPTables forward port to another ip:port but keeping original source ip

I have following iptables rules on gateway machine(192.168.0.1). I want to forward port 192.168.0.1:80 to 192.168.0.2:8080. But I need to maintain original source ip so that original server can get ...
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45 views

Firewall not starting on system startup

I have enable firewall using sudo ufw enable. But when i restart system, it is getting disabled. I checked /etc/ufw/ufw.conf and it has ENABLED=yes. Here is system config $ uname -a Linux master 3....
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52 views

How can i configure a rule that using squid3 for AVG update proxy base on an external firewall?

I'm using Ubuntu Desktop 14.04.3. The firewall i'm using is here http://gufw.org/. I've set up squid3 with a specific port. Now i want to configure the firewall rule to allow only AVG antivirus ...
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46 views

Block HTTPS site

Can anyone recommend an effective tool to block some https websites with ubuntu server? I want to use the server as a gateway for the users. A detailed guide would be highly appreciated. Thanks
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27 views

Block anything from NO-IP source

i have problem in my server there is to much load in my server and all process is 100% and at last server go down the only strange thing i can see there is to much request from no-ip how can i block ...
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UFW ACCEPT Problem

I'm having problem with UFW. If i block like whole /24 network becouse lots of bruteforcing etc. coming from China / Korea or somewhere. They still get to open ports. If i have, lets say port 443 ...
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1answer
808 views

Unable to connect to mongo on remote server

I have installed mongo on machine1(Ubuntu 14.04.3 LTS server) in my local network. I have also opened the port 27017 as mentioned in this guide using following commands: sudo iptables -A INPUT -p tcp ...
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1answer
95 views

Unable to add firewall rule “Duplicate Profile”

I'm unable to add new rules to my firewall using ufw gui. In the Log I get the following error. [19/01/16 14:16:43] Error running: /usr/sbin/ufw allow in from any to any port 8000 > WARN: ...
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126 views

OpenVPN Configuration with ufw eth0 doesn't exist to add it in before.rules

in this guide I am asked to edit /etc/ufw/before.rules and add: # START OPENVPN RULES # NAT table rules *nat :POSTROUTING ACCEPT [0:0] # Allow traffic from OpenVPN client to eth0 -A POSTROUTING -s ...