[zeromq-dev] does 0mq keep-alive for connections?

[Sergey Matveychuk]

Hi.

I have a ZMQ_PUB server (FreeBSD) and many (~300) ZMQ_SUB clients 
(FreeBSD and Linux). Sometimes I see a wierd problem on some Linux 
clients. netstat -a on server shows no connection with a client, but on 
the client netstat -a shows an established connection:

% netstat -a | grep 8542
tcp        0      0 client:54892      server:8542         ESTABLISHED

$ uname -a
Linux client.domain.net 2.6.32-33-generic #72-Ubuntu SMP Fri Jul 29 
21:07:13 UTC 2011 x86_64 GNU/Linux

Restarting clients makes it work again.

How is it possible? Have zmq a keep-alive mechanism for connections? Why 
I've never seen this behaviour on FreeBSD clients (just a luck)?

PS. 0mq 3.1