Score:0

UFW is inactive but traffic is still blocked

ru flag

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 this port when I run connection tests from other computers on the same network using telnet command. I've tried enabling and then disabling the UFW in hopes that may reset things but no luck. I've even tried enabling the UFW and adding rules to allow connections on port 8333 but still it didn't work.

Other ports do work fine (like 4000. I was able to reach the machine using telnet from another computer). What is it that I'm missing here?? please help this has been driving me nuts over the past few days ;-(

Terrance avatar
id flag
What is the output of `sudo lsof -i -P -n | grep LISTEN` and is port 8333 listed there? If there is nothing to listen on that port nothing can connect to it.
Score:0
ru flag

Apparently the firewalld service was running and filtering out the communication through port 8333. This is how I fixed it:

sudo firewall-cmd --zone=public --permanent --add-port=8333/tcp
sudo firewall-cmd --reload
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