Re: listening addresses

Andrew Dunstan <andrew(at)dunslane(dot)net> writes:
> A small problem with it was reported to me a couple of days ago - user
> had firewalled off all IP6 traffic. The stats collector happily bound
> and connected to the socket, but all the packets fell in the bit bucket.
> They found it quite hard to diagnose the problem.

> Possible solutions that occurred to me:
> . an initial "hello"-"yes i'm here" exchange to validate the address

That one seems reasonable to me. Seems like it would take just a few
more lines of code in the loop that tries to find a working socket to
check that we can send a byte and receive it. You'd have to be careful
not to block if the socket is indeed not working ... also, is it safe to
assume that a byte sent with send() is *immediately* ready to recv()?

regards, tom lane