fbclient of build 31529 takes a lot longer than previous versions to connect to Firebird 2.5, around 1 second vs some msecs.
This looks like a IPv4 / IPv6 issue on Windows, because if localhost is defined as 127.0.0.1 in etc/hosts, connects are as fast as with older versions of fbclient. If ::1 is also defined as localhost, connects are slow again.
First reported by Mark Rotteveel on firebird.devel.
This is surprising; if nothing listens on ::1/3050, connect() should fail (almost) immediately; it shouldn't take one second. This looks as if something was blocking the TCP reset (or ICMP port unreachable) sent in response to the SYN packet. But in such case, I would rather expect longer timeout than one second.
I was seeing this on Linux with fbclient 3.0.1 and 3.0.3, and any server 2.5.8 or 3.0.3, when connecting via ::1. When I connect via 127.0.0.1 it is fine. I see a delay of 1 second. However it turns out it was incorrect firewall rules delaying the attempted connection on ::1 from the 3.x client library. When this fails instantly it is fine again. Sorry for the noise but I couldn't delete this comment.