i'm trying to install the gns3 networking simulator on my kali linux so i checked the official website of this simulator www.gns3.com and i followed the steps but the first step raised a problem for me.
i run the first command which is :
sudo add-apt-repository ppa:gns3/ppa
which will add the gns3 to the repository so that i can install it easily with sudo apt install command but i got this error :
PPA for GNS3 and Supporting Packages. Please see http://www.gns3.com for more details
More info: https://launchpad.net/~gns3/+archive/ubuntu/ppa
Press [ENTER] to continue or ctrl-c to cancel adding it
gpg: keybox '/tmp/tmppjyx229p/pubring.gpg' created
gpg: /tmp/tmppjyx229p/trustdb.gpg: trustdb created
gpg: key 9A2FD067A2E3EF7B: public key "Launchpad PPA for GNS3" imported
gpg: Total number processed: 1
gpg: imported: 1
Warning: apt-key is deprecated. Manage keyring files in trusted.gpg.d instead (see apt-key(8)).
gpg: no valid OpenPGP data found.
if anyone can help.
thanks in advance!
