All Questions
Tagged with firewall networking
597
questions
0
votes
1
answer
24
views
How to match the --out-interface to the same --in-interface in iptables
The system have multiple interfaces: eth0, eth1, eth2, ... br0, br1, br2, ...etc.
The following rule will allow packets from "br0" to "br0":
iptables -A FORWARD -i br0 -o br0 -j ...
- 393
0
votes
0
answers
32
views
Cannot establish HTTP connection with VPS although ufw is allowing outside traffic
Here is the output of sudo ufw status verbose
Status: active
Logging: on (low)
Default: deny (incoming), allow (outgoing), disabled (routed)
New profiles: skip
To Action ...
0
votes
0
answers
14
views
Firewall to white- or black-list incoming requests
Well over a decade ago, when I was a Windows user, I used a Kaspersky firewall that would pop up when an application wanted was receiving a connection and allow me to allow or deny such connections.
...
- 2,821
0
votes
2
answers
111
views
Portforwarding Port 22 ( for ssh ) over JioFiber Router not working ( port 22 is closed )
I am using a JioFiber Router ( Firmware version : SRCMTF1_JCOW414_R2.52.1 ) . The host that I want to expose to the internet has Ubuntu Server 24.04.
Private IPs :
Router ...
0
votes
1
answer
31
views
Firewall ufw to deny port visibility
How can I block ports from being visible/accessible from the outside using ufw?
If I nmap my server I can see all my running Docker containers (all ports from 8080 to 8086), which I do not want, ...
- 2,513
0
votes
0
answers
58
views
Cannot start Ubuntu on WSL2
have a W10 device in test environment with clean WSL2 install, no distros. Installed Ubuntu. When attempting to launch I receive the error:
WslRegisterDistribution failed with error: 0x80072749
Error: ...
- 11
0
votes
0
answers
33
views
iptable-save command not showing any output
When i run iptables-save command on Ubuntu Ubuntu 22.04.3 LTS and Ubuntu 20.04.4 LTS it not showing default firewall chain rules when i run this other linux example centos or redhat i am able to see ...
0
votes
0
answers
68
views
Graphic Issues Firewall gfuw in Ubuntu 22.04.4 on RPI4 8GB
I'm running ubuntu mate 22.04.4 LTS on my 8GB Raspberry Pi 4. After not using the device for some weeks I ran all updates and upgrades. I noticed that the VNC remote access was no longer working so I ...
- 1
1
vote
0
answers
41
views
Unable connect via port knocking
I am trying to set up port knocking on my server to enhance security. I've configured my firewall rules to use port knocking, where I have to connect to specific ports in a specific sequence before ...
- 11
0
votes
0
answers
23
views
LAN network with just two computer: All ports time out, except port 50002, which refuses connection. Why?
Preface and Context:
I am currently troubleshooting the ROS2/LAN based connection of my UR5 CB3 robotic arm with the Ubunut 22 control comupter and the respective driver. This robotic arm seems to ...
- 19
0
votes
0
answers
35
views
Assistance Needed: Recovering Root Password and Accessing Firewall Settings on Ubuntu 20.04 Server
I am encountering issues with my Ubuntu 20.04 server running on Oracle, as I have forgotten the root password. Unfortunately, I am unable to access the GRUB menu to initiate password recovery. Could ...
0
votes
1
answer
76
views
Port not open (ufw disabled)
On the server, running Ubuntu 22.04
sudo netstat -tnlp | grep :4000
tcp 0 0 0.0.0.0:4000 0.0.0.0:* LISTEN 10690/nxd
tcp6 0 0 :::4000 ...
- 103
0
votes
0
answers
535
views
How to open port on wsl2 ubuntu of windows 11
To test the network between Windows 11 localhost and WSL2 ubuntu on Windows 11, I install tomcat9 on WSL2 ubuntu
$ sudo apt install tomcat9 -y
$ sudo systemctl enable tomcat9
$ sudo systemctl start ...
- 101
-1
votes
1
answer
2k
views
Use UFW (firewall) to deny incoming ping (ICMP) requests?
The ufw (uncomplicated firewall) command line app does not have any option for disabling incoming ICMP Internet protocol requests. ICMP is used mainly by ping to discover IP addresses of servers on ...
- 512
0
votes
0
answers
209
views
Connection refused from localhost in wsl2 ubuntu
I try to test connection between windows 11 and wsl2 ubuntu in windows 11. First I install nginx on wsl2 ubuntu and type in 'localhost' on web browser on windows 11 . The connection is successful. And ...
- 101
0
votes
1
answer
80
views
ufw won't put custom rule in the correct place at reboot
My general issue is that I lose contact with my Ubuntu 23.10 on ssh once I close my ports using knockd. I would like for it to maintain existing connections.
I have a custom rule
> iptables -I ...
- 160
0
votes
0
answers
35
views
How to enable communication between 'software' netplan configured vlans
I have searched far and wide so I if it looks like I have no idea what i'm doing, that is because it is a correct assumpstion. Usually we do this ourselves with our MikroTik router setup. We have a ...
0
votes
2
answers
281
views
LXC container cannot ping 8.8.8.8 or other outside ip
I run a LXC container on my "Ubuntu 23.04" VM by UTM on my mac laptop
but I cannot ping 8.8.8.8 in my LXC container.
I downloaded lxc via snap
note: I have search many info to fix the ...
- 1
0
votes
1
answer
270
views
Using Ubuntu 22.04 as DNS Server with bind9
I want to use a simple ubuntu 22.04 server as a DNS Server for my pc.
I created a new server, with a static ip address, that i will type in to my dns in windows.
My problem is, when i try
nslookup ...
- 1
0
votes
0
answers
192
views
ufw rule to allow address on the same subnet?
I have a server running Linux hosting a website. It uses ufw as a firewall. I have ports 80 and 443 open to external traffic. This all works.
Now what I want to do is allow any traffic from my laptop ...
- 109
0
votes
0
answers
128
views
Still getting [UFW BLOCK], which rules apply?
I still get a message UFW BLOCKED:
Dec 22 05:12:41 ge-domoticz kernel: [5324365.003868] [UFW BLOCK] IN=eth0 OUT= MAC=b8:27:eb:a1:7b:8b:38:1f:8d:e9:e4:9f:08:00:45:00:00:28:92:8c:00:00:ff:06:2f:d4 SRC=...
0
votes
1
answer
257
views
Port Forward for LAN
I bought a server and have Ubuntu 22.04 installed.
When I run various Github projects like Text Generation Webui, Automatic1111 Stable Diffusion, etc., how do I forward the port to access it from my ...
- 103
0
votes
0
answers
157
views
Ubuntu 23.10 keeps inconsistently blocking incoming connections (from machines on the same subnet)
I have a fresh install of Ubuntu 23.10. It's running on a PC at home, and is only Wi-Fi connected. I've enabled ufw, and have allowed web traffic as I'm using this to mock up a Wordpres site for ...
0
votes
0
answers
44
views
nginx running and port allowed, but on client side is closed
I have a server was running fine with port 443, but not it's not running.
using command sof -i -P -n | grep LISTEN, i get:
nginx 3124 root 6u IPv4 39437 0t0 TCP *:443 (LISTEN)...
0
votes
2
answers
469
views
Cannot access any service running on ubuntu server including SSH
Problem: I'm unable to access any service running on by Ubuntu 22.04, including SSH. This server has been running for months without any issues. It currently hosts a frontend as well as 3 different ...
1
vote
0
answers
95
views
Strange UFW Block Logs
i noticed repeats of the following logs in my server:
Dec 3 21:55:27 alice-server kernel: [287677.084885] [UFW BLOCK] IN=ens18 OUT= MAC=01:00:5e:00:00:01:90:9a:4a:dc:31:62:08:00 SRC=192.168.0.1 DST=...
- 11
0
votes
0
answers
348
views
Ubuntu 22.04 iptables command not working
I posted this same question in another SE forum, later felt this forum is more appropriate considering the Linux Distro I am dealing with.
Totally new to netfilter thing, currently am running an ...
- 101
0
votes
0
answers
30
views
I'm attempting to execute a Flask test file, but when attempting to access it through the browser, an error stating that the site cannot be reached
I have tried creating an inbound rule in my firewall to allow port <5000> but its still showing site cannot be reached.
i have also tried to Check UFW (Uncomplicated Firewall) with this command
'...
- 1
1
vote
1
answer
178
views
Can only access some servers on Linode VLAN
I am running a VLAN applied to a number of servers on Linode. The IPs assigned are 10.0.16.n/24 and are accessed via an OpenVPN server also on the same range.
I have connected to the VPN box from my ...
- 279
0
votes
1
answer
250
views
The download manager loses its access to the Internet after working for a while in ubuntu 23.10.1
I use download manager in Ubuntu but after a while it works fine and the internet access is blocked!
I tested Free Download Manager and Xtreme Download Manager both of them at first work correctly but ...
- 117
0
votes
0
answers
286
views
Setting up a reverse proxy on home lab
I'm very new to Linux and bash. I'm working on a homelab (machine a) project.
My ultimate goal is to set up Nginx on my server and connect externally (machine c) to Docker apps File Browser, possibly ...
- 1
0
votes
0
answers
258
views
How to deal: external Jenkins port does not work
I have jenkins service working fine on internal and local levels (I can just open localhost:8080 or 192.168.x.x:8080 in the browser and it gives me Jenkins "sign in" page)
But I have ...
- 101
4
votes
1
answer
955
views
I can't connect to Ubuntu server from local network, but can from outside
This is a weird one that has been driving me crazy for a while. I just can't work it out.
I'm running Ubuntu 22.04 (with all latest patches) on a Dell PowerEdge-r710 server. It's hosting a variety of ...
- 143
0
votes
1
answer
664
views
Ubuntu Router configuration with UFW
Going down the ubuntu 20.04 server route and using UFW.
Steps so far (from a clean install)
Network Layout attached
networking configured with netplan - YAML file below - question here is do I need ...
- 1
1
vote
1
answer
156
views
BIND9 on Ubuntu 20 - Cannot configure Zone to work properly
I installed it on Ubunto 20 and configured two zones
Options config file
acl internal {
localhost;
localnets;
192.168.70.0/24;
10.200.157.0/24;
};
options {
...
- 11
0
votes
0
answers
170
views
Restrict access to Docker container port to ip adresses
There are several docker containers on my server, exposing ports. Now I try to restrict the access to the ports to IP-Adresses being able to insert rules without allowing the policy. I apply IP-Tables ...
- 1
0
votes
0
answers
2k
views
SSH Connection Timed Out Ubuntu 20.04
I've looked through a million threads on this topic but nothing has worked. I'm trying to ssh into my linux through port 22. Connection is refused.
UFW is inactive and firewall-cmd is not downloaded
...
- 1
0
votes
0
answers
73
views
Automatically created iptables rules created by Docker seem strange
Here are the rules that I don't understand (those are created automatically by docker on my ubuntu machine):
-A FORWARD -i docker0 ! -o docker0 -j ACCEPT
-A FORWARD -i docker0 -o docker0 -j ACCEPT
So ...
2
votes
0
answers
113
views
External HTTPS succeed, internal HTTPS requests timeout on home server
I am running Ubuntu Server 22.04.3. I am using it to serve an API built on Flask, which goes through Gunicorn and NGINX to hit the outside world. The server works as expected for requests served over ...
- 121
0
votes
1
answer
146
views
Port Forwarding to another machine Rust gameserver
I need to forward UDP port 28015 of my local machine to another machine with port UDP 28021. Rust Game Server. (Redirect incoming traffic on a specific port to a different IP address with altern port)
...
1
vote
0
answers
608
views
wireguard + ufw = unable to limit access to specific port
So I'm trying to limit access to port 5432 (postgres) by using ufw and unable to do so. The connection is allowed still
sudo ufw deny 5432/tcp
sudo ufw route deny in on wg0 from 10.0.10.2
root@vpn-...
- 141
0
votes
0
answers
701
views
Connection via SSH works once or twice then never again for that client
I have recently set up a Ubuntu Server minimized. I initially used the server through an SSH with client1 but after one use I kept getting Connection Timed Out when attempting to ssh from client1. I ...
1
vote
1
answer
771
views
UFW blocking port forwarding
I am running Ubuntu Server as a home network router, which works fine otherwise. I also have another server on the network which hosts all of my content and services. So let's say, for example, I'm ...
0
votes
0
answers
756
views
curl to localhost fails in 20.04
I have host machine 20.04 and guest VM box 22.04
I am trying to run the curl command and on both machine getting the same error.
Host running this:
sudo ufw status
Status: active
To ...
- 15
0
votes
1
answer
49
views
Network card issues after reinstall of 20.04
PC with PCI Lan card and motherboard Lan had previously worked fine on 18.04 and 20.04, was upgraded to 22.04 but found application compatibility issues so reinstalled 20.04. Now the integral Lan is ...
0
votes
0
answers
301
views
Diference between IPTABLES RAW PREROUTING and MANGLE PREROUTING
I'm looking for configs to prevent DDoS attacks and UPnP Flood, since I've started to create rules, every advice was to add rules to filter table, but it takes too much CPU process, so started to ...
0
votes
0
answers
34
views
allow certbot validation and github action connection to digitalocean network firewall
I have this digitalocean droplet that I served as staging instance and has network firewall on it. As it is a staging instance I made it work like a private access only by adding our outline vpn ip on ...
- 101
0
votes
1
answer
156
views
Unable to remote access the web server running on Ubuntu machine
I'm unable to remote access nginx server or express server or any server running on Ubuntu in the same network
I tried every solution found on Google, chat gpt but no benefit
I'm able to ssh on Ubuntu ...
- 1
0
votes
0
answers
180
views
Ubuntu - Tool for UDP rate-limit
I have a SIP gateway machine that I would like to apply some kind of rate limit on the host machine.
Something like - If an X number of connections happens under Y seconds -> Block source-IP and ...
0
votes
0
answers
53
views
Uable to connect Ubuntu server by remoting
Hello I'm newbie of Ubuntu system. I have some problem that I've figured out for a while but I could not solve it yet. I could not remote to Ubuntu 22.04 server from my laptop (Putty said connection ...
