PATCH: longish HELO in dccm.c

Vernon Schryver vjs@calcite.rhyolite.com
Fri Oct 18 18:28:22 UTC 2002


> From: Leandro Santi <lesanti@uolsinectis.com.ar>

> ...
> The following patch fixes a problem with long smtp HELO arguments
> in dccm.c. See the patch for more deailts, it is quite obvious in fact.
> ...

Thanks.  I'll include it in version 1.1.16.

What SMTP client has a HELO value longer than MAXHOSTNAMELEN+30?
By chance, are you not stripping the ESMTP chatter from the HELO value?
Or do you not use that big a buffer for HELO values?

The main change for 1.1.16 will be to let clients retry DCC reports
as queries to other DCC servers.  The current tactic is just give up
after a tries to a server that doesn't respond, to avoid reporting
the same checksums more than once when the problem is not that the
server is down but that the client can't hear the server's answer.

This change seems interesting because there is a lot of mob behavior
in the 1000 clients using the 7 servers answering dcc.dcc-servers.net.
In one hour, one of those servers will be receiving 5 requests per
second while the others are less busy.  In the next hour, the busy
server will be almost idle and the mob will be huddled around another
server.  I theorize that is caused by transient high packet loss rates
in the Internet.  Such losses beg doing something to mitigate their
other effects.


Vernon Schryver    vjs@rhyolite.com



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