Questions tagged [firewall]

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

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ubuntu ngnix aws lightsail server cant able to access via putty

After changing the firewall settings in the server. I cant able to access via putty. I tried to install ssl certificate, where I supposed to change the firewall settings. I also tried rebooted the ...
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What does rule section ufw-not-local do?

While using ufw for my Ubuntu 22.04, I try to understand the iptables structure behind it. What concerns me specifically is this snippet taken out of /etc/ufw/before.rules: # # ufw-not-local # -A ufw-...
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What happens with empty iptables?

From that answer, and other comments on the same webpage, I came to the conclusion that ubuntu by default has an empty iptables. However, people said it was safe, because unless the unexperimented ...
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ufw blocks incoming FTP traffic (on port DPT=44745)

I have JVM app which is dealing as client with FTP, it works fine when ufw is disabled, but when I enable ufw with: ufw allow ftp Check status output is then: Status: active Logging: on (medium) ...
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Hotspot only works after starting and stopping already disabled ufw service

I have recently decided to try out firewalld instead of ufw. After installation I ran these two commands to theoretically make the switch sudo systemctl disable ufw and sudo systemctl enable firewalld....
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OenVPN connection failed, port is not opening with ufw (code=111)

Im trying to set up an openvpn on my pc (which is running Ubuntu Server 22.04). I've used the quick install script listed here When i try to connect on my linux machine i get the following error: 2022-...
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Block ubuntu running device from accesing a specific local ip

I have a tiny server running 24/7 and I would like to make it unable from accesing my router which is on the 192.168.1.1 IP.
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My server can't connect to anything through 443

I tried to connect to paypal, github and stripe from my server and every connection attempt ended with a "connection timed out". I use ufw as my firewall I have the default incoming rule is ...
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ufw is not closing port for incoming packets even after i set the rule?

I am trying to stop steam from opening my port 27036. The problem is that even after i enabled ufw, and even after manually setting a new rule to block this port (even tho by default it should block ...
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Ubuntu Server 20.04 random ports are timing out, and I don't know why

I need to access a webserver on my Ubuntu Server 20.04 installation. For a test, I set up a webserver using sudo python3 -m http.server <port>. It works fine for a bunch of ports, like 8000, 443,...
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allow different ssh auth from specific but different IPs?

Is it possible to setup login rules for ssh users, for example: address1,address2 = incoming IP1, incoming IP2 User bernie is only able to connect from address1 User seb is only ...
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Open server port 80 and redirect to container IP

I'm not an heavy user of unix based systems. And I have some trouble opening a server's port (80) to the public and redirect it to a running container. So basically, I have a running container on a ...
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Ubuntu 20.04 ssh possible but NO Access on custom port

Fresh install of 20.04 LTS on Small Form Factor Intel user@host:~$ cat /proc/cpuinfo processor : 0 vendor_id : GenuineIntel cpu family : 6 model : 76 model name : Intel(R) Pentium(R) CPU ...
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Incoming connections getting blocked on some ports with no firewall rules Ubuntu server

I'm a relatively inexperienced Linux user and I'm having issues with connections to my machine. I'm using Ubuntu Server 20.04 LTS I have a web server, a samba server, a game server and a ssh server ...
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UFW disabled/inactive on reboot

I'm having an odd issue where ufw gets disabled on reboot. I'm running kubuntu 21.10 and ufw 0.36.1. My uname -a output is: Linux HOSTNAMEHERE 5.13.0-39-generic #44-Ubuntu SMP Thu Mar 24 15:35:05 UTC ...
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UFW blocking vpn connection - firewall killswitch

I have a very strange problem! UFW is blocking vpn connection: despite I allowed it in firewall (UFW). It is not router! When I disable UFW it works! I used this guide to set it up: https://www....
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UFW Deny out on specific adapter except for LAN traffic, VPN usage

I have two interfaces on a VM, one is traffic going out to web on VPN adapter (proton0) and the other should allow lan traffic (ens160). The rules make sense to me however, I cant ping a lan address ...
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iptables Explicit Allow Policy

I am attempting to setup an Explicit Allow policy on my 20.04 Ubuntu web server. By running the following: iptables -P INPUT DROP Also added rules for ssh, http and https. Resulting in the following ...
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How to block traffic when strongswan ikev2 tunnel not established

Strongswan ikev2 network manager plugin network-manager-strongswan was installed on ubuntu 20.04.4 and configured to reconnect automatically. However when VPN is not available I'd like to block all ...
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UFW not blocking IP address

I am trying to block an IP address from my server. ###ufw status verbose Status: active Logging: on (low) Default: deny (incoming), allow (outgoing), disabled (routed) New profiles: skip To ...
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How do I use UFW to block a device in Ubuntu hotspot?

I have a laptop running Ubuntu 20.04, which connected to the internet via ethernet. I have setup a WiFi hotspot on this machine, so that I can share its internet connection. Say, I have third device (...
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How to test if firewall is working/troubleshoot it?

So I recently moved my media server to a new computer and moved from popOS to Ubuntu 21.10. I have NPM set up on docker as a reverse proxy and have port 80 and 443 forwarded on the router to my server....
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how to allow java to firewall for minecraft

I am playing Minecraft on Linux and it won't connect to the server stuck on connecting to the server how to allow the java to the firewall?
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ufw exclude internal IPs from logs

I have a test HTTPS server running on Linux server (Ubuntu 20.04.4) on port 20000. I would like to log all connections on this port. So I did this, and it works fine. ufw allow log-all 20000/tcp Now, ...
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Port forwarded on router, Port Open on PC, Port setup with python server to listen. Port check tools still say it's closed

UFW is disabled, I used iptables to open the port. If I do netstat -tulpn then it says the port is in a listen state. On the router I have the port forwarded to the linux machine. I figured maybe it ...
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How to set up UFW port forwarding from non-privileged port to port 22 on the same computer

On my Ubuntu server, I am running an SSH server (port 22). I want to set up UFW such that all incoming connections are blocked, except through port 12345. External traffic arriving at port 12345 ...
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UFW firewall create connection issues

I have installed UFW on my VPS server using apt install ufw when I use ufw enable to start the firewall, after that my putty session expires and I can no longer login with that ssh key I have either ...
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iptable rules to allow downloading stuff while default policy is on DROP

I was trying to install bind and for some reason I was getting issues most likely due to my iptable rules , I can ping google.ca anybody have any reccomndations down below are my current rulesets ...
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I wanted to allow outgoing DNS traffic while OUTPUT is on DROP

I currently have a dns server running on my pi , and I am using that as my dns I wanted to ping google.ca while my output chain / input being on drop here are my firewall rules would love to hear some ...
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Allow incoming traffic from ipv6 address

So here´s my problem. I changed the internet provider recently. Now I have an ipv6 address only. On my linux server, I used a bash script, to update the iptables rules due to my ipv4 address changing ...
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Port 80 showing as filtered, ufw inactive

sudo nmap -sS 3.139.146.153 PORT STATE SERVICE 22/tcp open ssh 25/tcp filtered smtp 80/tcp filtered http 443/tcp open https 3306/tcp open mysql 7000/tcp open afs3-...
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UFW VPN Killswitch doesn´t work, stopps all traffic?

So Nordvpn's new update basically messed up the killswitch and I wanted to set up one myself in order to maintain some basic privacy. I followed this guide mainly: https://adamtheautomator.com/linux-...
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Why do I have dropped incoming packets from various IPs?

I have an Ubuntu VM serving as a WireGuard peer. My network only has my WireGuard port forwarded to my VM (51820 to 192.168.1.2). I think my iptables (below) are set up to only allow (1) SSH from my ...
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IPtables firewall rules - Ubuntu

Can you please explain to me the difference between this 2 IPtables rules, there were implemented to transfer packets from external internet users to a local server : iptables -t nat -A PREROUTING -p ...
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Traceroute shows request timeout message with stars

When I try to run traceroute in my Ubuntu Virtual Machine (Oracle) it only shows the first hop(self hop) and then it shows * * * and request timed out message traceroute to www.amazon.in (108.158.254....
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Firewall: enable access on selected ports on external IP but allow any port on local IP Ubuntu 20.04 LTS

How do I allow all traffic that occurs on VLAN / internal ports without any blocking but on external IP I allow selected ports. so I want the machines on VLAN to communicate freely but I want ...
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Yet another SSH connection timeout [closed]

This one is puzzling me to no end. By using PuTTY (latest version) I was able to connect from Windows 10 to Ubuntu 18.04 via SSH (local network), and I've been doing it for over a year until it ...
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SSH Over VBox NAT NOT Working Ubuntu 20.04 Host (desktop) Ubuntu 20.04 server (guest)

I can get internet on guest by setting vbox adapter 1 to bridged network adapter and host-guest communication works when I set adapter 2 as a host-only adapter This is sufficient if I don't want to ...
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Problem on open my Plesk panel from specific IP

I have a Plesk panel that is installed on Ubuntu 20.04. I can open websites, mail, and Plesk control panel from anywhere. But I can't open the website, mail, and Plesk from a specific IP. I trusted my ...
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Ubuntu as Gateway and Firewall doesn't NAT the router

I want to configure a network like this: Modem (local ip: 192.168.178.1) -> PC Ubuntu Server 20.04 with 2 LAN as Firewall and Gateway -> Router (local ip: 192.168.178.6) -> Switch->... ...
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Firewall settings for remote (VPN) subnet?

I have two servers running 18.04.6 desktop. I am unable to access them from a different subnet (IPsec site to VPN). It appears to me that the built-in firewall doesn’t allow connections from an ...
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UFW is inactive but traffic is still blocked

on my Ubuntu 20.04 LTS desktop, i have the UFW firewall disabled (status inactive). I'm running bitcoin core application which listens on port 8333. Though the UFW is inactive, I cannot connect to ...
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Why do I see login requests for various ports although the router and the firewall only permit port 22?

I want to login into the Desktop of my Ubuntu 18.04 machine remotely from the internet. I therefore enabled port forwarding for port 22 in my (fritz.box) router. Additionally I activated the firewall ...
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How do I open ports 443 and 8080 on a virtual Ubuntu Server 20.04.3?

I am running Ubuntu 20.04.3 server as a virtual server. My virtual server was virtualized with VMware and the delivery was automatic. I'm going to set it to use outline and I have to open ports 443 ...
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Best Practices for persisting nftables rules

I'm new to Ubuntu having moved from hosting on CentOS7 which was using iptables and I was comfortable with how apf and bfd handled (hid) iptables from me.. and it was working well So, I've moved to ...
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Unable to open port 443, despite apache listening, ufw open locally on machine

Hello fellow ubuntu lovers. I've been trying to open port 443 on my server (on a private network) for some time, but I'm stuck. It's open on ufw, and apache is listening to that port, but somehow I ...
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How to apply IP-Based Bandwidth limiting in Linux

i have a linux machine which connected to a layer 2 edge Switch , how can i setup this linux machine to act as firewall or router to do ip-based or macAddress-based Bandwidth limiting for other nodes ...
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System Management with egress firewall filtering

I have a contractor that manages firewall and security. They are moving to egress web filtering. I am all for security, but I have a few months to make sure that this does not break my toys...systems. ...
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No internet access without VPN after updating from 18.04 to 20.04

After updating to Ubuntu 20.04 LTS internet stopped working without VPN (I use Cloudflare WARP) righthaze@desktop  ~  ping google.com PING google.com (216.58.215.110) 56(84) bytes of data. ping: ...
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paranoid outgoing-whitelist firewall

it might seem somehow unusual, but I would like to have a whitelist ip address list for outgoing connections in my firewall it seem like afer 30 entries of ip-range the list was full, unable to hold ...
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