Name resolution from a jail

[YONETANI Tomokazu <qhwt+dfly@xxxxxxxxxx>]

Hello.
ISTR posting a similar report a half year ago, but I'm not sure
if it's related or not...  This occurs on -DEVELOPMENT, not on
1.6.1-RELEASE (but I haven't tried 1.6.2 yet).
I just did a `make DESTDIR=/path/to/jail installworld' in advance
to make sure that the jail is up-to-date with the jail host.

Depending the program, the source address of UDP packets from the
DNS query shows up corrupted in netstat -anfinet output:

$ cat /etc/resolv.conf
domain .
nameserver 192.168.2.175

$ w
 6:13PM  up  2:52, 1 user, load averages: 0.19, 0.25, 0.13
USER             TTY      FROM              LOGIN@  IDLE WHAT
(press control+Z here, as it's stuck on reverse name resolution)
$ netstat -anfinet |fgrep .53
udp4       0      0 64.125.66.215.1119    192.168.2.175.53
                    ~~~~~~~~~~~~~
                    this address doesn't belong to our network.

$ host 192.168.2.251
251.2.168.192.in-addr.arpa has no PTR record

Same thing happens to sshd, so I need to set `UseDNS no' in sshd_config
or I can't slogin to the jail(but even with this option, sshd tries
a reverse name lookup and fails).  So it seems that `host' command is
using a different resolver library from `w' or `sshd' (if it's a library
problem).

The same problem doesn't happen on the jail host.

The jail node is assigned an IP address 192.168.2.251/32 which is an
alias address of the jail host, which has 192.168.2.250/24.

Regards.