[vsskanth]

Is there a P2P file transfer program that doesn't require any Internet connection, even for establishing the handshake ?

[canistel]

Localsend? https://localsend.org/

[LordShredda]

Probably SCP, but modern firewalls and routers automatically block that port and no one thought of making a half decent GUI

[indianets]

P2P within LAN?

For anything outside your LAN, 2 nodes must need a negotiator(over internet) to know each other unless the nodes already have public dedicated IPs in which case they can talk to each other securely without the need of a negotiator.

[GreenVulpine]

rsync

[BiteCode_dev]

One could create it using zeroconf but i'v yet to see one software do that.