I noticed the same thing, this goes for any non-windows box ive scanned
Preparing for retry, open port 161 noted
Preparing for retry, open port 167 noted
Preparing for retry, open port 163 noted
Done with round 0
The UDP or stealth FIN/NULL/XMAS scan took 24 seconds to scan 21 ports.
Interesting ports on (x.y.z.q):
Port State Protocol Service
151 open udp unknown
152 open udp unknown
153 open udp unknown
154 open udp unknown
155 open udp unknown
156 open udp unknown
157 open udp unknown
158 open udp unknown
159 open udp unknown
160 open udp unknown
161 open udp snmp
162 open udp snmp-trap
163 open udp cmip-man
164 open udp cmip-agent
165 open udp unknown
166 open udp unknown
167 open udp unknown
168 open udp unknown
169 open udp unknown
170 open udp unknown
171 open udp unknown
Final times for host: srtt: -1 rttvar: -1 to: 6000000
Nmap run completed -- 1 IP address (1 host up) scanned in 25 seconds
Received on Dec 20 1998