Wireshark-users: Re: [Wireshark-users] Use of User DLT

From: Guy Harris <guy@xxxxxxxxxxxx>
Date: Thu, 23 Jul 2009 18:04:20 -0700

On Jul 21, 2009, at 10:44 AM, Mahesh K wrote:

I get the following error "No such proto:ldm". Now I do see that the ldm dissector is successfully registered.

Unless you've used register_dissector(), you have *not* successfully registered the dissector by name - and the "Payload protocol" item in the encapsulations table is really the payload *dissector*, not the payload *protocol*.

You might have registered the *protocol* with proto_register_protocol (), but there isn't necessarily a one-to-one correspondence between protocols and dissectors (there might be multiple dissectors for the same protocol, depending on whether, for example, extra metadata is supplied for the protocol outside the packet data, or whether the packets have an FCS, or whether the protocol is running atop TCP or not, or....)