[zeromq-dev] Assert in signaller.cpp on XP if Cisco VPN Client is installed

Martin Robinson martin.robinson at dai.co.uk
Fri Mar 22 11:25:53 CET 2013

I've found an interesting issue which is causing me a bit of a


We have an application which we have recently re-written to use ZeroMQ
as a messaging layer (version 3.2.1).


It works very nicely, except when running on a Windows machine which
also has the Cisco VPN Client installed. The VPN client does not need to
be connected - it just needs to be installed for the problem to show up.


What I have found is that we get a crash (wsa_assert fail)  at line 310
in signaller.cpp. This is the connect call in


The connect seems to fail with a 'Connection refused' error. Why on
earth would this connect fail? We have just opened the listener socket


Curiously, it only fails the 2nd time this code is executed - the first
time works. I suspect this is something about the way the listener
socket is created, a connection accepted, then the socket is closed an
reopened again quickly.  There appears to be some strange interaction
between the 'Deterministic Network Enhancer' and winsock which causes
this code to fail.


Any ideas welcomed!





Martin Robinson
Senior Systems Engineer


York House,  4 Wolsey Business Park

Tolpits Lane,  Watford,  WD18 9BL
Tel: +44 1923 815408   Fax: +44 1923 235786

Web: http://www.dai.co.uk/transport <http://www.dai.co.uk/transport> 


The integrity of this message cannot be guaranteed on the

internet. DAI cannot therefore be considered responsible for the

contents, unless confirmed in written correspondence signed by

an authorised signatory. If you are not the intended recipient of

this message, please delete it and notify the sender.



-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.zeromq.org/pipermail/zeromq-dev/attachments/20130322/e544b4cf/attachment.htm>

More information about the zeromq-dev mailing list