[prev in list] [next in list] [prev in thread] [next in thread] 

List:       netbsd-tech-net
Subject:    multicast NTP sends pkts with class-D source address?
From:       Jonathan Stone <jonathan () DSG ! Stanford ! EDU>
Date:       1999-02-11 2:04:53
[Download RAW message or body]


I'm configuring xntpd-3.93c to use multicast on a single subnet.

I have a netbsd 1.3H (i386, old current) running as a stratum-3
multicast server. 

The dratted NetBSD (1.3H, yes its old) box answers unicast chimes sent
by its multicast clients properly, except that the source address
comes out as a multicast address:


7:25:34.277891 cup burner ip 90: NTP.MCAST.NET.ntp > Burner.DSG.Stanford.EDU.ntp: v3 \
sym_act strat 2 poll 10 prec -18 dist 0.002990 disp 0.152404 ref \
MightyDog.Stanford.EDU@3127685089.271494865 orig 3127685114.088747411 rec \
+0.025272933 xmt +20.189020723 (ttl 64, id 56545)


Now, rfc-1112 says all hosts should silently drop such packets.
so conforming Linux boxes ignore these.

rfc-1112 also says that, if unspecified, the src address shouldbe the
address of some outgoing interface.  My guess is, xntpd is using a
socket on which it's bound to 224.0.1.1, but that's just a guess
(ktrace -d doent show anything more useful than a sendto()).
I'll try this tomorrow on -current.

Meanwhile, has anyone else seen this?


[prev in list] [next in list] [prev in thread] [next in thread]