From: Andrew Simmons (andrews@mis-cds.com)
Date: Tue Jan 13 2004 - 15:28:30 EST
Paul Johnston wrote:
> I've come accross the following anomoloies while auditing a network, can
> anyone help explain what they are:
>
> 1) Ports that "hang open" i.e. you can connect, send data ok, but the
> other end never sends any data and never closes the connection.
Do you get any banners back to help identify the services, or use nmap
version scan? If so do they match anything well-known? Do the servers agree
with the remote OS? (eg IIS running on Solaris?)
> 2) HTTP ports that function normally when you issue some methods, but on
> other methods (including the imaginary method "SILLY") cause the
> connection to "hang open" like in (1).
Could possibly be an application layer proxy?
> 3) Ports where the TTL is different on the SYN reply to the rest of the
> connection. ipid's also imply that different hosts are handling the SYN
> and the rest of the connection.
>
> I've got some theories, but I'm not sure how much I'm jumping to
> conclusions.
>
I guess you're thinking proxies or firewalls with 'security servers' (eg
Checkpoint) - although I don't know what the IPIDs,TTLs etc look like in
that situation. Hmmm, I think I just found a lab project for next week :)
> Paul
>
cheers
\a
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