Questions tagged as ['firewall']

a technological barrier designed to prevent unauthorized or unwanted communications between computer networks or hosts
Score: 0
viiprogrammer avatar
No internet access without VPN after updating from 18.04 to 20.04
ma flag

After updating to Ubuntu 20.04 LTS internet stopped working without VPN (I use Cloudflare WARP)

righthaze@desktop  ~  ping
PING ( 56(84) bytes of data.
ping: sendmsg: Operation not permitted
ping: sendmsg: Operation not permitted
ping: sendmsg: Operation not permitted
--- ping statistics ---
3 packets transmitted, 0 received, 100% packet loss, time ...
Score: 0
Thorsten Kiefer avatar
paranoid outgoing-whitelist firewall
bd flag

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 any more

is there a solution

like eg /etc/hosts.out.allow


Score: 0
"This site can't be reached, try checking the proxy, firewall, and dns configuration" error
in flag

After my Wi-Fi is connected and my data stays on, I am unable to access the Internet. I get:

This site can't be reached, try checking the proxy, firewall, and dns configuration".

What can I do please? It’s been two weeks now.

Score: 1
ip forward to another interface with ufw doesn't work
pk flag

I'm trying to setup an IP forward. Cannot manage to make it work. The goal is to receive a connection on interface1 (IP on this interface is port 4443, and send it through interface2 to IP (dest IP) port 4443.

  • I enabled "net.ipv4.ip_forward = 1" in /etc/sysctl.conf
  • setted DEFAULT_FORWARD_POLICY="ACCEPT" in /etc/default/ufw
  • added that to /etc/ufw/before.rules (from various tut ...
Score: 1
Ali najjar avatar
Firewall setting are correct but port still closed form outside
cn flag

I setting up machien for connect to postgresql remotly I check somthing and it's apeare all things is correct

Checking the port status :

$> sudo netstat -tulpn | grep LISTEN | grep 5432

tcp 0 0* LISTEN 18134/postgres

Checking the firewall

$> sudo ufw status | grep 5432

5432 ALLOW Anywhere

Ping inside machine work :

$> telnet 185.235.x.x 5432

Connected to 185.235.x ...
Score: 1
ssh: port 22 Connection refuses
es flag

I have a question regarding remote access a machine via ssh. I'm trying to ssh login to my linux machine from my mac and I already setup the ssh-server on my ubuntu, opened the 22 port and firewall. However, I got these error message while connecting

[@Ges-MacBook ~]->ssh <username>@<remote machine's ipv4> -vvv 

OpenSSH_8.6p1, LibreSSL 2.7.3 

debug1: Reading configuration data /etc ...
Score: 0
Cannot connect to Ubuntu 20.04 server through ssh locally, only through the outside
mx flag

I created a ubuntu server today, and everything was working nicely, even managed to change the port. Couple hours later, I cannot use "ssh -p 2606 dragos@", only "ssh -p 2606 dragos@376.326.622.942" (fictional adress).

When running "ssh -p 2606 dragos@" I get the error message "ssh: connect to host port 2606: No route to host", when running "ssh -p 2606 dragos@37 ...

Score: 0
dos4dev avatar
80 port Connection refused
cn flag

I am new to Ubuntu firewall and I have Ubuntu 20.04 server.

All ports 8080, 81 ... are externally available, but when I tried telnet IP 80 I received telnet: Unable to connect to remote host: Connection refused

ufw status verbose is:

Status: active
Logging: on (low)
Default: deny (incoming), allow (outgoing), deny (routed)
New profiles: skip

To                         Action      From
--                 ...
Score: 0
Petro Gromovo avatar
Can I consider my OS Safe after I installed firewall?
ms flag

After ubuntu 20 installation I installed firewall with main options:

hoster@hoster-laptop:/project$ sudo ufw allow ssh
Rules updated
Rules updated (v6)
hoster@hoster-laptop:/project$ sudo ufw enable
Firewall is active and enabled on system startup
hoster@hoster-laptop:/project$ sudo ufw default deny incoming
Default incoming policy changed to 'deny'
(be sure to update your rules accordingly)
hoster ...
Score: 0
RHT9855 avatar
Iptables block ping from another ip
cn flag

I am a beginner in the field could you help me please

me :

user1 :

user2 :

I would like to block ping from user1 to user2 using iptables from my ip

So I made this: iptables -t filter -A INPUT -p icmp -s -d -j DROP

But it doesn't work, in fact I don't even know if it's really possible to block ping from another ip ...

Score: 0
Vivek Sura avatar
Ping not working. Internet working in ubuntu
cn flag

I use ubuntu 18.04. I cannot ping from my ubuntu terminal nor make REST API calls from my Ruby On Rails console since a few months. The only relevant change I made on my laptop is to install ExpressVPN on my linux machine. Here are few things I tried.

  1. ping on ubuntu laptop with "Ethernet from router-1" - Not Working
  2. ping on ubuntu laptop with "WiFi from router -1" - No ...
Score: 0
Firewall monitoring and notification
cn flag

On windows platform I always use netpeeker for having an eye on my network activity. It allows to see any process that have outbound connection or listening on any port plus each process bandwidth usage. Another feature is when I double click on any process it shows which port(s) the process using and what address/port is connected and finally the most interesting part for me is ability to define rule t ...

Score: 0
Oscar Newport avatar
probleme running ufw on Ubuntu 20.04.3
pk flag

I'm new to Ubuntu and to try it out I've installed the Ubuntu app from Microsoft store and running it on my windows 10 laptop, I tried to enable the UFW but I got this:

:~$ sudo ufw enable

ERROR: problem running ufw-init
iptables-restore v1.8.4 (legacy): iptables-restore: unable to initialize table 'filter'

Error occurred at line: 1
Try `iptables-restore -h' or 'iptables-restore --help' for more  ...
Score: 0
Unable to acess my services using public ip address
in flag

I am running Ubuntu 20.04.3 LTS 64-bit

My local network IP has been DMZ and the port i'm looking to use is forwarded.

when I start my NodeJS process, it is listening on ip on the selected port.

By runnning sudo netstat -tulpn I get the confirmation.

> tcp     0    0*        LISTEN    11480/node

Now when I run ifconfig I get this output

docker0: flags=4099<UP ...
Score: 1
Mike Higgins avatar
Cannot reach some WEB pages
in flag

A few weeks ago I was able to browse any WEB page from FireFox on my Ubuntu 20.04 desktop system. Now some WEB pages time out. For example, no problem accessing, but I time out trying to reach one of my own WEB pages hosted on GoDaddy (for example If I plug my Windows 10 laptop into my same LAN next to this Ubuntu system, the laptop can reach any WEB pag ...

Score: 1
how to open specific tcp port on ubuntu
sj flag

I am on Ubuntu 18.04, I am trying to run python -m http.server 8080 and everything works, I can connect to the server from other computers but if I change the port to: python -m http.server 8501 I cannot connect to the server...

I tried disable ufw by sudo ufw disable to allow port 8501, does not work I tried the netstat and it says the system is listen on I tried iptables didn't find anythin ...

Score: -1
How do I open a port on my Ubuntu 14.04 virtual server to my Mac from which it runs?
cl flag

I’m running a virtual Ubuntu (14.04) box, using Vagrant, on my Mac Big Sur machine. I would like to open port 1234 on my virtual machine to my Mac. From the virtual machine, I can see these ports listening

$ sudo lsof -i -P -n | grep LISTEN
[sudo] password for myuser: 
mysqld    1425   mysql   19u  IPv4  21538      0t0  TCP *:3306 (LISTEN)
sshd      1447    root    3u  IPv4  24616      0t0  TCP ...
Score: 1
Why is ufw not blocking traffic from
jp flag

My ufw is enabled and only permits ssh and wireguard:

# ufw status
Status: active

To                         Action      From
--                         ------      ----
22/tcp                     ALLOW       Anywhere                  
51820/udp                  ALLOW       Anywhere             
22/tcp (v6)                ALLOW       Anywhere (v6)             
51820/udp (v6)             ALLOW       Anywh ...
Score: 0
Nigel Wash avatar
Iptables that only allow incoming traffic to OpenSSH and block all other traffic
cn flag

I need to configure a firewall using iptables that only allows incoming traffic to the openssh services and block all other traffic. I know how to block all incoming traffic but don't know how to only allow incoming traffic to the openssh and block all other incoming traffic simultaneously. I also need the ssh to be logged as "ssh traffic" and all the other blocked traffic to be logged as "blocked traff ...

Score: 0
Mr. Kips avatar
My internet won’t work, how do I fix it?
tr flag

So I have Ubuntu 20.04 with a wired ethernet connection. I have noticed one day that web browser could not load anything so I checked my internet in the settings and it said that I have a connection, so I checked the ufw (which has disabled my browser before) and it too was not it (but I made sure using ufw disable and also checking the gufw, which is the gui version without the terminal). So I tried ...

Score: 0
Sriram Rayadurg avatar
Update UFW rules from a text file
cn flag

I have a list of ip's (almost 55K) that i want to deny from a text file. I would like a script to read from the text file and update the ufw status.

Is there anything like that?

At present I am doing this

while read line; do sudo ufw insert 1 deny from $line to any; done < filename.txt

This takes a hell long of a time. Would a script be faster?

Score: 1
Diskless Ubuntu client - UFW enable hangs system
hk flag

I have successfully created diskless Ubuntu system instance via this community help page and it works perfectly. However, I would like to enable firewall with UFW and when I tried to do that the problem appeared.

As part of the tutorial on help page I prepared complete "filesystem" with other installation and already bootstraped OS with my settings there (installed necessary packages, changed con ...

Score: 0
Adam avatar
Kubuntu firewall blocking internet access after downloading UI
aw flag

We've tried setting up a plex server on two occasions, and both of these times we've run into trouble where the commands for allowing ports on the firewall does not work, so we end up downloading the firewall UI from discovery.

After just downloading the application, what happens is that we lose internet access, and we have to execute :

sudo ufw reload

everytime we start these computers.

It's real ...

Score: 0
Gigiux avatar
I installed firewall-configuration and lost the wifi
eg flag

to keep the PC safe, I installed firewall-configuration from Ubuntu software:

enter image description here

As soon as the installation was over, I lost the WiFi connection (and even Rstudio cannot connect with R, by the way). I removed it with sudo apt-get remove firewall-config but the WiFi is still dead.

How can I reestablish the wifi? and do I need a firewall in ubuntu? and an antivirus? (if yes, is clamAV OK?)


Score: 0
AdhamH99 avatar
Ubuntu server UFW issues
br flag

I was sending requests to my server using postman. Then, something went wrong and all of my requests were blocked. Now, I can't send requests or even access the server using the IP address unless I use a VPN.

I am a student learning and I am pretty lost — I don't know where to start. I searched for hours on how to reset UFW and disable and enable and even adding new rules didn't work. Below is  ...

Score: 0
Yabesh avatar
while checking the ufw status for using nginx server in ubuntu app in windows, getting error. Can't get solved this issue?
vn flag
 yabesh@LAPTOP-DLAQ7R33:~$ sudo ufw status
 ERROR: problem running iptables: iptables v1.8.4 (legacy): can't initialize iptables table 
`filter': Table does not exist (do you need to insmod?)
 Perhaps iptables or your kernel needs to be upgraded.


I inst ...

Score: 0
piza avatar
Tomcat 9 port 8080 no access after installing Filemaker
in flag

OS: Ubuntu Server 18.04 Software: *Claris Filemaker Server 19(Installing Java automatically with needed other *dependancies) / *360Works Mirrorsync 6 / *Tomcat 9


I run fms(Filemaker Server) with 360works mirrorsync. Single server to fm go clients.

I need to setup tomcat in order to get mirrorsync to work. The tomcat installation steps that the mirrorsync support staff refer to requires steps  ...

Score: 0
user654789384 avatar
UFW - Secure Workstation
mx flag

Im typically using default rules:

sudo ufw default deny incoming
sudo ufw default allow outgoing
sudo ufw enable

I would like to close everything (outgoing) what i dont use. I would then do the following:

sudo ufw default deny incoming
sudo ufw default deny outgoing
sudo ufw enable

So right now everything is blocked. What im looking for is a logfile, which shows me what port has been blocked. Exampl ...

Score: 1
does adding a rule to iptables mean it takes effect immediately?
in flag

I run sudo iptables -A INPUT -p tcp -m tcp --dport 2222 -j ACCEPT in bash and then tried to connect to that machine via another machine on the same LAN / subnet via port 2222 with PuTTY and it didn't work.

Maybe I need to restart iptables after I add the rule for it to take affect? If so how would I do that?

Here's the output of iptables -S:

-N DOCKE ...
Score: 0
Arjun Ganta avatar
Unable to add rules to iptables in Ubuntu 18.04
fr flag

I am trying to add rules to allow port 161 in iptables . But it is giving below error while executing this command "sudo iptables -L"

iptables v1.6.1: can't initialize iptables table `filter': Permission denied Perhaps iptables or your kernel needs to be upgraded.

I am using latest version of iptables.