Sudden and strange problem

[Oriental Sensation]

Hi guys,

No idea if this is related to FreeBSD but hopefully someone could help me.

Couple of days ago I upgraded to 10.1-PRERELEASE and something
happened. My configuration is a host with 2 jails -- the host runs
unbound and the two jails use it to resolve. There's one local zone
entitled "local" and few hosts to identify the jails: dbs.local,
smtp.local, www.local, etc. One jail runs dovecot+postfix and the
other runs a web server.

There's a really strange thing going on because occasionally trying to
telnet from the web server to the other jail (port 25 or 143) takes
few seconds, but most of the time it takes a millisecond. I did a
'truss' and 'drill' and I am attaching 2 links to the logs:

http://pastebin.com/rUrq10vd
(look at line 276, I surrounded it with empty lines because that's
where the delay happens -- this time for 2 seconds)

http://pastebin.com/Q3W3dhLM
(again, I inserted spaces around line #151 where 5 seconds in delay -- twice).

By the way, running the same commands few times after, no delay is apparent.

Anyone got an idea what on earth is causing this?

Thanks in advance for any help.

/OriS