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Avahi/mDNS

Agama's Live ISO is configured to use mDNS (sometimes called Avahi, Zeroconf, Bonjour) for hostname resolution. The reason is that it might be quite difficult to find out which URL should be used for connecting to a running Agama installer.

This document explains how this feature works and offers a few hints for fix potential problems.

Warning

Do not use the .local hostnames in untrusted networks (like public WiFi networks, shared networks), it is a security risk. An attacker can easily send malicious responses for the .local hostname resolutions and point you to a wrong Agama instance which could for example steal your root password!

Firewall Configuration

If you cannot connect to a server using the .local domain then maybe the firewall is blocking the traffic. Then you need to enable the mDNS traffic using these commands:

# enable the mDNS traffic in the current run
firewall-cmd --zone=public --add-service=mdns
# make the change permanent
firewall-cmd --permanent --zone=public --add-service=mdns

Using mDNS

The Live ISO by default uses the agama.local hostname. To connect to the running instance simply type https://agama.local in your browser. In most browsers the HTTPS is the default protocol so usually it is enough to just type agama.local.

If you run multiple Agama instances, each one will have a different name. The server appends a number to make it unique. So the second Agama instance gets the agama-2.local hostname.

If you are not sure whether there are multiple Agama instances running you scan the network, see the service advertising below.

Alternatively you can set a different hostname for each instance manually. Use the hostname= boot option to set a different hostname. For example set hostname=foo, hostname=bar and then use https://foo.local, https://bar.local URLs in the web browser to connect to the respective instance.

It is possible to change the hostname later if needed:

# set the new hostname
hostnamectl hostname <hostname>
# restart the avahi daemon server
systemctl restart avahi-daemon

The mDNS resolution also works for other services like ping or SSH. So you can use commands like:

ping agama.local
ssh [email protected]

Fallback

The mDNS approach is just an addition, one more possibility how to connect to the machine. If it does not work for you then you can always use the old good classic IP address approach.

Service Advertising

The Agama Live ISO also uses Avahi service advertising. With this you can easily search for all running Agama instances in the local network:

avahi-browse -t -r _agama._sub._https._tcp

The command will print the found servers and their hostnames and IP addresses.

Notes

  • mDNS works only in the same local network, it does not work over internet or separate network segments.
  • mDNS might not be supported in all systems or it might be blocked by firewall.
  • On mobile phones with Android OS mDNS is supported since Android version 12. (but this might be vendor dependent...).