debian:/etc#  nmap -A -T4 localhost

Starting Nmap 4.11 ( http://www.insecure.org/nmap/ ) at 2007-12-12 22:33 IST
Interesting ports on localhost (127.0.0.1):
Not shown: 1675 closed ports
PORT     STATE SERVICE VERSION
25/tcp   open  smtp    Exim smtpd 4.63
80/tcp   open  http    Apache httpd 2.2.3 ((Debian) PHP/5.2.0-8+etch7)
111/tcp  open  rpcbind  2 (rpc #100000)
113/tcp  open  ident   OpenBSD identd
3306/tcp open  mysql   MySQL 5.0.32-Debian_7etch3-log
No exact OS matches for host (If you know what OS is running on it, see http://www.insecure.org/cgi-bin/nmap-submit.cgi).
TCP/IP fingerprint:
SInfo(V=4.11%P=i686-pc-linux-gnu%D=12/12%Tm=47601480%O=25%C=1)
TSeq(Class=RI%gcd=1%SI=2BBE0A%IPID=Z)
TSeq(Class=RI%gcd=1%SI=2BB3F3%IPID=Z)
TSeq(Class=RI%gcd=1%SI=2BA77E%IPID=Z)
T1(Resp=Y%DF=Y%W=8000%ACK=S++%Flags=AS%Ops=MNNTNW)
T2(Resp=N)
T3(Resp=Y%DF=Y%W=8000%ACK=S++%Flags=AS%Ops=MNNTNW)
T4(Resp=Y%DF=Y%W=0%ACK=O%Flags=R%Ops=)
T5(Resp=Y%DF=Y%W=0%ACK=S++%Flags=AR%Ops=)
T6(Resp=Y%DF=Y%W=0%ACK=O%Flags=R%Ops=)
T7(Resp=Y%DF=Y%W=0%ACK=S++%Flags=AR%Ops=)
PU(Resp=Y%DF=N%TOS=C0%IPLEN=164%RIPTL=148%RID=E%RIPCK=E%UCK=E%ULEN=134%DAT=E)


Service Info: OS: OpenBSD

Nmap finished: 1 IP address (1 host up) scanned in 16.451 seconds