Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!CISCO.COM!cire
From: cire@CISCO.COM (cire|eric)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: Does anyone use IP options?
Message-ID: <8908290825.AA23996@ucbvax.Berkeley.EDU>
Date: 29 Aug 89 03:57:59 GMT
References: <11990001@hpspdra.HP.COM>
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 49

>> Date: 28 Aug 89 17:39:37 GMT
>> From: hpl-opus!hpspdra!jpeck@hplabs.hp.com  (Joe Peck)
>> Subject: Does anyone use IP options?
>> 
>> I have a few question about IP options.
>> 
>> 	How often are they used?  How common is it to see IP frames 
>> 	with options in the header?

It isn't very common.  There was a time when certain options in the packet
would cause certain hosts to crash.

>> 	What programs cause IP options to be used?  I know that there 
>> 	is a version of PING that supports the IP Record Route option.
>> 	What other programs invoke IP options?

It is entirely up to the OS implementation to allow access to that level.
Most do not.  SUNOS does provide the interfaces and there are a number of
administration tools that exist that take advantage (ie. traceroute).

cisco routers provide the functionality for ping via the extended commands.
Various things can be specified including Loose Source Route, Strict
Source Route, Record Route, and Time stamp.

>> 	Do most or all IP implementations support IP options?  I don't
>> 	want to start any finger pointing, I'm just interested in
>> 	whether the majority do or don't provide option support.
>> 

It depends on the implementation.  I haven't heard of a crash blamed on
options in quite a while so I suspect that most implementations coexist
peacefully.

>> 
>> Thanks,
>> 
>> Joe Peck


-c
cire|eric

Eric B. Decker
cisco Systems - engineering
Menlo Park, California

email:	cire@cisco.com
uSnail: 1360 Willow Rd.,  Menlo Park, CA  94025
Phone : (415) 326-1941