While learning about p2p networks I found out that P2P networks need signaling servers but can modern DHT replace the need for signaling servers? (Holepunching mainly)
A vanilla DHT that only acts as hash table can't serve that purpose but a customized implementation where the nodes support some protocol-specific extensions it is possible. E.g. in the bittorent DHT clients can instruct DHT nodes to put whatever their externally visible port is into the hash table rather than simply publishing their internal port number. This only really works for full-cone NAT.
For restricted cone or symmetric nat more complicated signalling and guessing approaches like STUN would have to be added to all DHT nodes and peers behind NATs could then initiate traversal at a particular node by publishing it as their rendezvous.