Traditional SunOS didn't generate checksums on UDP packets. This
was a hack to make NFS faster.
What it also did was occassionally allow corrupt DNS responses
not to be detected. And because the DNS requestor would cache
the response, that corruption couldn't be recovered from until
the DNS TTL (usually 1-10 days, 3 recommended) had expired.
This was a real problem in Australia, where we had a DNS
forwarder on the Australia side of the AU--US link to
reduce traffic on the link. Ditto most other non-US
countries.
To give you idea of the scope of the problem, the NANOG
mailing list cooperated in tracking down all the machines
running DNS name servers with UDP checksumming disabled
and e-mailed the NS contact.
Please don't take us back to those days. I suspect the
problem would now be insoluble, because of the huge
number of Internetworked machines, the increased amount
of spam and the decreased clue of DNS administrators.
Cheers,
glen
-- Glen Turner Network Specialist Tel: (08) 8303 3936 Information Technology Services Fax: (08) 8303 4400 The University of Adelaide 5005 Email: glen.turner@adelaide.edu.au South Australia- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/