On Thu, May 5, 2011 at 11:29 UTC, Miroslav Lichvar wrote: > Hi, > > RFC 5905 has in section 5.1.1.: > > /* > * Verify valid root distance. > */ > > if (r->rootdelay / 2 + r->rootdisp >= MAXDISP || p->reftime > > r->xmt) > return; /* invalid header values */ > > > But it seems that ntpd (at least 4.2.6p3 and 4.2.7p162) doesn't have > the reftime > xmt check, only the distance check, is that correct?
I dug into the source code history. The check was removed by Dr. Mills on 2008-07-16 in ntpd/ntp_proto.c 1.274, part of a largish set of changes identified as "Bias and interleave stuff from Dave Mills", first seen in 4.2.5p120. This was also during a period of weedwhacking by Dr. Mills to bring the code in line with the specifications. I have included links below detailing the entire set of changes. It occurs to me interleaved operation involves "funny" xmt timestamps, so it would make sense if the check were removed to avoid rejecting legitimate interleaved traffic. Dr. Mills, do you recall? http://lists.ntp.org/pipermail/bk-ntp-dev-send/2008-July/001337.html http://ntp.bkbits.net:8080/ntp-dev/?PAGE=cset&REV=487dbed3vkMKdxRFVpFK4DSMo_u-1g Cheers, Dave Hart Cheers, Dave Hart _______________________________________________ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
