Wireshark · Wireshark-dev: Re: [Wireshark-dev] How to avoid dissection based on port defined by a different dissector?

[Dirk Jagdmann <doj@xxxxxxxxx>]

> The problem I have with this is that 3503 is registered to MPLS Echo so that
> dissector shouldn't have to be changed to essentially become a heuristic one to
> accommodate this port-stealing protocol.  It's essentially the same situation as

There is no port stealing. The IANA list is just a list, it does not enforce
anything or forbid other developers to choose one of these ports for his service.

In addition not nearly every TCP/UDP application out there has tried to register
their port with IANA. If you've read the rules to do this and have tried to
register something with them, you might know that it is often not worth the hassle.

Wireshark already has the perfect solution with 1) heuristic dissector, 2)
manual selection which dissector to use for a TCP conversation.

I don't think we should go ahead a pro-actively change all dissectors which are
not heuristic, but if a port clash occurs the developer who wants to submit a
new dissector should convert the existing one to heuristic and make his new one
heuristic as well. Or simply live with the fact, that some other dissector might
"win the lottery" which one gets choosen for a packet.

-- 
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