We do use DNS, but we also have an option for node discovery that uses pkarr.org, which is using the bittorrent mainline DHT and therefore is fully decentralised.

And, as somebody else remarked, the ticket contains the direct IP addresses for the case where the two nodes are either in the same private subnet or publicly reachable. It also contains the relay URL of the listener, so as long as the listener remains in the same geographic region, dumbpipe won't have to use node discovery at all even if the listener ip changes or is behind a NAT.

    we also have an option for node discovery that uses pkarr.org, which is using the bittorrent mainline DHT and therefore is fully decentralised