Name resolution from a jail
qhwt+dfly at les.ath.cx
Wed Jan 17 01:45:19 PST 2007
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
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 0 184.108.40.206.1119 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
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.
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