Questions tagged [firewall]
a technological barrier designed to prevent unauthorized or unwanted communications between computer networks or hosts
1,242
questions
0
votes
1
answer
19
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
26
views
Why Ubuntu 22.04 Network Manager sends messages to blackcat.canonical.com in two IP addresses?
Here are the netstat -tnp output captures from my Ubuntu 22.04 workstation. Why are there outbound NetworkManager connections established from time to time? What are they doing?
The IP addresses ...
- 13
-2
votes
0
answers
23
views
Ping IP Linux Ubuntu
PT-BR
Estou utilizando Ubuntu e preciso descobrir a latência de um IP de um subdomínio. Tentei primeiramente o comando "ping", mas sem sucesso. Também tentei chegar se a porta 53 e 80 ...
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
1
answer
56
views
Disable Internet access but allow chrome extension
I'm trying to deny access to the Internet and that part works with ufw default deny outgoing (the PC is going to be used for exams so no googling allowed;-))
But
I need access to a chrome extension ...
-1
votes
0
answers
31
views
SSH not working on port22 after checking open port, updating UFW, port fowarding on router and confirming internet carrier ports status with carrier
This is my first time trying to make an SSH tunnel. The purpose is to make an offsite backup our server (server A) in the office which is about 1 mile away.
I have set up all ports on the office ...
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
0
answers
57
views
UFW not logging [UFW BLOCK] events when default is to allow incoming connections
I'm trying to get a message logged to /var/log/ufw.log when blocking packets. It's all working very well, until I change the default behaviour for incoming connections.
I use ufw default allow ...
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
28
views
AXIOS/Fetch - Error on Ubuntu
Axios or Fetch data from external API Error on Ubuntu 22.04, but if using local API or try on my Windows, it can work.
0
votes
0
answers
53
views
Ports show as open when nmaping to localhost but filtered when connecting to IP
My 22.04.4 Ubuntu server was installed on a Proxmox VE. Then I installed Discourse forum on top of it (it uses Docker).
Now, after successful installation the Docker's 443/80 ports show as closed when ...
0
votes
0
answers
40
views
How to allow direct connection to plex media server
im trying to set up plex media server on ubuntu server os.
i installed the plex media server and when im trying to watch in the same network everything is ok.
the problem starts when i try to stream ...
- 21
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
0
votes
0
answers
32
views
Jammy 22.04 Attaching a pro subscription
when I try to attach my UbuntuPro subscription it keeps failing with no real error message.
lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 22.04.4 LTS
...
- 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
0
answers
27
views
Why tor need icmp in outbound iptables?
I'm trying to block everything in outbound except tor with iptables.
But without enabling icmp tor doesn't work, it's very strange since tor don't use icmp as my understanding.
That's what I'm using ...
0
votes
0
answers
33
views
firewall is enable but gufw wont lauch
The firewall is enabled. But I can't launch gufw interface.
sudo ufw status
Status: active
- 1
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
62
views
Specify L2TP VPN to use other port
I am currently at a hotel and they seem to block VPN use. I assume they block it by looking into the port it uses.
I would like to use my company VPN (L2TP). So, I think my best bet is to change the ...
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 ...
1
vote
1
answer
136
views
What are the use cases of "continue" verdict in the nftables?
It is described in the documentation of nftables as:
continue
Continue ruleset evaluation with the next rule.
This is the default behaviour in case a rule issues no verdict.
But I am ...
- 43
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
0
answers
47
views
Checking this network connection (port forwarding)
I have the below setup, I want to be be able to reach the device (192.168.2.180 eth) from my desktop (192.168.1.3 wifi) I have a linux server in the middle (192.168.1.111 WIFI), (192.168.2.22 Eth)
...
- 11
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
3
votes
3
answers
316
views
Having issues locking down public server with iptables
I'm rather new to Ubuntu. I'm trying to lock it down to where I have complete access to it from my ip address and everyone else only has access to port 80 and 443.
To better understand it, I put my ...
- 521
0
votes
0
answers
112
views
Why I lost my internet connection when in windscribe console I set “Firewall” option "On"?
I have installed windscribe on my kubuntu 22.04 but when I run windscribe console and set “Firewall”
option on - I lost my internet connection.
I think the reason could be that I have windscribe ...
- 135
0
votes
1
answer
323
views
vsftpd fails LIST command even when firewall is off and on localhost
I installed vsftpd and am using ufw as my firewall. I can connect to the ftp server, login, and change directories, but any attempt at using a LIST command times out from both external and localhost. ...
- 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)...
2
votes
1
answer
532
views
3proxy, plain HTTP proxy, "Failed to connect"
I'm trying to configure 3proxy on Ubuntu 22.04, following the instructions on the developer's website as well as tutorials from the internet. I need a standard HTTP proxy. All HTTP and HTTPS ports are ...
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
2
votes
1
answer
565
views
Strange dmesg UFW messages... lots of them
I've done some digging but haven't been able to find something that explains below message I found in dmesg? It's obvious the UFW firewall is blocking something, but I am not having any success in ...
- 111
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
213
views
Can access self-hosted Portainer website from internet trying to lock server down without any luck
I'm new to Docker & Portainer and I'm trying to lock it down from public access where it's not needed.
My setup:
Windows 2022 Server running Hyper-V (host)
Ubuntu 22.04 Workstation (virtual ...
- 521
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