A problem in ndp and rtadvd.

[Iverson Hsieh -謝承恩]

Dear all:
   I use command, date, to set current time. I find this causes the two 
problems. I test the following two cases in freebsd 5.5-STABLE and 
in freebsd 7.0-BETA2, and I find the result is the same.
 
1.in neighbor discovery protocol(ndp)
   The following is my command sequence.
   
$ ndp -a
Neighbor                                              Linklayer Address  Netif   Expire         S Flags
2001:b121:4::cccc                                0:50:8d:48:57:9a    fxp0   permanent   R
2001:b121:4:0:41f7:42ee:d08c:ca8c    0:90:cc:c2:aa:61    fxp0    26s              R
9999:9999::1                                        0:5:1c:15:a:8b       rl0       permanent   R
fe80::205:1cff:fe15:a8b%rl0                0:5:1c:15:a:8b       rl0       permanent    R
fe80::250:8dff:fe48:579a%fxp0           0:50:8d:48:57:9a    fxp0   permanent   R
fe80::290:ccff:fec2:aa61%fxp0            0:90:cc:c2:aa:61    fxp0    30s              R
fe80::1%lo0                                         (incomplete)         lo0       permanent    R
 
$ date
Fri Mar 21 16:14:18 UTC 2008
 
$ sudo date 0703211614
Password:
Wed Mar 21 16:14:00 UTC 2007
 
$ ndp -a
Neighbor                                               Linklayer Address  Netif  Expire           S Flags
2001:b121:4::cccc                                0:50:8d:48:57:9a    fxp0   permanent     R
2001:b121:4:0:41f7:42ee:d08c:ca8c    0:90:cc:c2:aa:61     fxp0    366d0h0m4  R
9999:9999::1                                        0:5:1c:15:a:8b        rl0       permanent    R
fe80::205:1cff:fe15:a8b%rl0                0:5:1c:15:a:8b        rl0       permanent     R
fe80::250:8dff:fe48:579a%fxp0           0:50:8d:48:57:9a    fxp0   permanent     R
fe80::290:ccff:fec2:aa61%fxp0            0:90:cc:c2:aa:61     fxp0   366d0h0m4   R
fe80::1%lo0                                         (incomplete)           lo0       permanent    R
===============================================================================================
   
   I adjust system current time to one year ago by using 'date' command. we can find
ndp expiration time, in Expire column, also extended one year. Is this OK?
 
2.in router advertisement daemon(rtadvd)
   I also adjust system current time to test rtadvd. Before I adjust system
current time, rtadvd can send unsolicited RA periodically. rtadvd can send
unsolicited RA about from 200 seconds to 600 seconds each time. But after I 
adjust system current time to one year ago, rtadvd does not send unsolicited 
RA any more. Is the behavior correct?