[zeromq-dev] Can I make a ROUTER ignore a client's ZMQ_IDENTITY?

[Pieter Hintjens]

On Sat, Dec 28, 2013 at 12:32 AM, Tom Nakamura <tnakamura at eml.cc> wrote:

If I expose
> a ROUTER socket to unknown/untrusted clients, then the router may get
> multiple connections with the same identity by accident or malice
> resulting in a denial of service.  Or am I missing something in the way
> routers work?

You can't ignore identities. However duplicate clients with the same
ID will be treated as anonymous (their ID will be ignored) so there is
no risk of a denial of service. You can switch off that behavior using
ZMQ_ROUTER_HANDOVER, which lets clients "steal" connections by
specifying an already-used ID.

-Pieter