It contains netdb.nlm, but may not install it under NW3.12. The latter currently appears to have found favour. Adding a small amount of technical info here. DHCP is designed like this. A client needing service broadcasts for servers.
Servers send an initial offer to the client.
The target server replies with a formal written offer and the client accepts. The interesting step is in the middle where the broadcast reply is sent, designed as a broadcast so all other servers can hear the client pick one server. In the packets are the offered IP address, so in principle the other servers could mark that IP address as being in-use. This is just plain dumb, but what else does one expect of committees and convoluted specs. There is a humorous replay of all this.