Questions: nmap, nessus unreliability, setting up a packet capture box, using Impacket

[Paul Johnston <paul () westpoint ltd uk>]

Hi,

1) How reliable have people here found nmap and nessus to be? I have 
encountered (rare) cases of nmap not finding ports, and also of nessus 
not identifying ports during the find_service stage. We hear a lot about 
false positives, but it's much harder to notice false negatives. 
Anything that can be done about this?

2) I'm looking at setting up a box to capture all traffic on our 
scanning network. Does anyone have thoughts on doing this, based on 
their operational experiences?

3) Using Core Impact's Impacket library, how can you get it to calculate 
UDP or TCP checksums correctly? No matter what I do they won't come out 
right. It works fine for ICMP. While I'm on the subject, what do people 
use for raw packet libraries? I really like scapy for interactive use, 
but it seems a bit heavyweight for use in scripts.

Regards,

Paul

--
Paul Johnston
Internet Security Specialist
Westpoint Limited
Albion Wharf, 19 Albion Street,
Manchester, M1 5LN
England
Tel: +44 (0)161 237 1028
Fax: +44 (0)161 237 1031
email: paul () westpoint ltd uk
web: www.westpoint.ltd.uk



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