[zeromq-dev] 0MQ and Firewalls

Pieter Hintjens ph at imatix.com
Tue Oct 5 06:26:48 CEST 2010

On Tue, Oct 5, 2010 at 4:01 AM, John McLaughlin - PTIR
<john.mclaughlin at promise.com> wrote:

> Is there a officially defined position with regards to 0MQ’s ability to work
> in a client/server architecture where the client might be behind a
> firewall/NAT-router?  If so, where can I find this documented?

The connectivity guarantees are exactly those defined by each
transport.  Thus with TCP you can create outgoing connections across
firewalls/NAT, but not incoming ones.

0MQ supports this insofar as it lets you switch the connect/bind roles
arbitrarily, so your 'server' can connect to your 'client' if the
server is on the inside of the firewall/NAT.

It's orthogonal to messaging patterns and multipart.  PGM is
disconnected and does not cross firewalls/NAT (afaik) unless
explicitly forwarded.

If you need this to be formally specified the right place would be the
reference manual: http://api.zeromq.org/zmq_tcp.html

Pieter Hintjens
iMatix - www.imatix.com

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