Re: Cisco 677 oddity: Broadcasting to port 1999

[Blue Boar <BlueBoar () THIEVCO COM>]

Jim Duncan wrote:
> Port 1999 is the Cisco Discovery Protocol.  It was deprecated a long time
> ago, I don't believe it's available by default anymore (if it is we'll try
> to get it turned off), I don't think anybody uses it for anything useful,
> and the whole subject of why it exists, what it does, why it's not useful
> anymore, and what to do about it has been beaten to death several times on
> several mailing lists, most notably BUGTRAQ around 1999 February, I think.
> Anybody that wants to avoid rehashing old issues can search the archives.

CDP certainly exists still, it's just now a layer-2 protocol, and very
much on by default.  It's used by various types Cisco equipment to
find each other.  The only use I've seen for this is when you want to
autodiscover your network with something like Ciscoworks.  Ciscoworks
only has to contact some arbitrary first router, dump the CDP table,
and then it will have all the next hops from that point, as well
as switches, etc...  Lots of interesting info is carried in the
CDP frames, such as hardware platform, software version, name,
and protocol addresses.

Jim, you probably knew all of this, but your statement didn't come out
like you did.  (i.e. I think you're saying the port 1999 version
of CDP doesn't exist... not CDP in general.)  Also FYI for the
rest of the readers.

                                        BB

P.S. What was the address to report problems to again?  I didn't
catch it in your e-mail. :)