bad zone transfer request

[bizbox]

hi ,
     i have been receiving this on my bind log lately

May 06 17:02:42.257 xfer-out: info: client 65.2.121.121.1083: bad zone 
transfer request: 'domain.com/IN': non-authoritative zone (NOTAUTH)

using a tcpdump this is wat i observed:

17:02:15.179594 ns.dns.com.domain > 65.2.121.121.4929:  18261 1/2/2 
(169) (DF)
17:02:42.231689 65.2.121.121.1083 > ns.dns.com.domain:  24576 SOA? 
domain.com. (32)
17:02:42.231931 ns.dns.com.domain > 65.2.121.121.1083:  24576 1/4/4 
SOA[|domain] (DF)
17:02:42.257073 65.2.121.121.1083 > ns.dns.com.domain:  16384 [1n] 
Type251? domain.com. SOA[|domain]


any idea wat is happening?is the client connecting having some 
misconfiguration??kindly shed some light.thanks