The problem Holesail solves

Create P2P tunnels instantly that bypass any network, firewall, NAT restrictions
and expose your local network to the internet securely,
no Dynamic DNS required.

Create Network Tunnels
Secure your Network
Bypass any Firewall

Challenges I ran into

Problems:

Working the same software on different operating systems.
How to establish connection between n systems.
Solutions:

Used the technologies or methods which are OS independent and work it on localhost environment.
By generating a hash code through data hash table as an identity and connecting sender and reciever through Kademlia Algorithm.