> Transmitting all IP addresses in the clear might be bad, sending out hashes might be better How many IP adresses are valid? Can't you hash them all and compa

> Transmitting all IP addresses in the clear might be bad, sending out hashes might be better How many IP adresses are valid? Can't you hash them all and compare them with the hash you receive? 2^32 IPs is 4GB * 4 Bytes (1 IP) + 4GB * size of the hash should be the needed space I think.