Re: rfc 1122 and ICMP SOURCE HOST ISOLATED
barns@cove.mitre.org Tue, 15 November 1994 17:49 UTC
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Cc: Gabriel.Montenegro@eng.sun.com, braden@isi.edu, Steve.Drach@eng.sun.com, postel@isi.edu, Kent@bbn.com, barns@cove.mitre.org
Subject: Re: rfc 1122 and ICMP SOURCE HOST ISOLATED
In-Reply-To: Your message of "Fri, 11 Nov 94 16:56:16 PST." <199411120056.AA21711@zephyr.isi.edu>
Date: Tue, 15 Nov 1994 12:28:20 -0500
Sigh, I propose 6-10 are "hard", 11-12 are "soft", and 13 (if it was ever really allocated??? "Communication administratively prohibited") is "hard". It seems practical to treat 6 as "hard", but we're somewhat inconsistent with our religion here. Isolated is not administrative, it's an error condition in the network; it means "almost all destinations are unreachable due to network or host glitch". In retrospect, I wonder if the code is even a good idea; not only is the means of detection net-specific (which is OK with me) but the meaning of the message is somewhat net-specific. If there is no carrier on your ethernet interface should your kernel synthesize Dest Unreachable code 8 when you try to send out that ethernet interface? Does anyone actually do this? ICMP sure is a mess. But this seems to be a morass for everyone (look at X.25 and ISO 8208 - 10 times as many error codes, same inconsistency among implementations, too many codes, people don't use specific codes when they should, there are not enough codes to describe all diagnostic information without loss of information, ...) There's probably a paper in this somewhere - "Self-Similar Disparity in Error Code Allocations"...
- Re: rfc 1122 and ICMP SOURCE HOST ISOLATED braden
- Re: rfc 1122 and ICMP SOURCE HOST ISOLATED Jon Postel
- Re: rfc 1122 and ICMP SOURCE HOST ISOLATED barns
- Re: rfc 1122 and ICMP SOURCE HOST ISOLATED Gabriel Montenegro