On Fri April 8 2005 11:48, Tony Finch wrote:
On Tue, 5 Apr 2005, Bruce Lilly wrote:
Routes in paths (forward and reverse) generally are modified in transit.
Routes in paths are now somewhat uncommon, but are not obsolete and
should not be ignored in a description of the mail system architecture.
They've been strongly deprecated since RFC 1123 (dated 1989) which states
that this is for architectural reasons. Therefore I think it's legitimate
for a modern description of the architecture to omit source-routed paths
on the grounds that they are ana anomalous historical relic.
See section 5.2.6 of 1123. Also, routes are still sometimes necessary
to work around temporary DNS and related problems (I've had to use them
several times in the past few years).