da hat pertze schon vollkommen recht, kaumt läuft ein daemon wie proftpd oder apache kann nmap schon sehr viel damit anfangen. Am besten alles abschalten was geht und
options TCP_DROP_SYNFIN
in den Kernel bauen,
tcp_drop_synfin="YES"
in der rc.conf eintragen
Starting nmap 3.50 (
http://www.insecure.org/nmap/ ) at 2004-02-29 14:19 CET
Warning: OS detection will be MUCH less reliable because we did not find at least 1 open and 1 closed TCP port
All 1659 scanned ports on korg (xxx.xxx.xxx.xxx) are: closed
Too many fingerprints match this host to give specific OS details
Nmap run completed -- 1 IP address (1 host up) scanned in 13.854 seconds
sobald nur mein sshd läuft:
TCP/IP fingerprint:
SInfo(V=3.50%P=i386-portbld-freebsd4.9%D=2/29%Time=4041E77C%O=22%C=1)
T1(Resp=Y%DF=Y%W=8000%ACK=S++%Flags=AS%Ops=MNWNNT)
T2(Resp=N)
T3(Resp=N)
T4(Resp=Y%DF=N%W=0%ACK=O%Flags=R%Ops=)
T5(Resp=Y%DF=N%W=0%ACK=S++%Flags=AR%Ops=)
T6(Resp=Y%DF=N%W=0%ACK=O%Flags=R%Ops=)
T7(Resp=Y%DF=N%W=0%ACK=S%Flags=AR%Ops=)
PU(Resp=Y%DF=N%TOS=0%IPLEN=38%RIPTL=148%RID=E%RIPCK=E%UCK=0%ULEN=134%DAT=E)