Hi Dave,
Scanning a firewalled system is obviously difficult. One way to likely accomplish this is to not bother with TCP ping (common tcp service SYNs, attempting to solicit a response to let Nessus know that the host is alive) and simply port scan the system over a broad range of ports.
You can then use the list of open ports to scan the system with by feeding the IP and port list to Nessus.
Depending on the type of host firewall and the rules/exceptions enabled, you may not be able find any ports. As the saying goes, your mileage may vary.
There are other ways to find services with methods like firewalking, but this is more about hacking or pen-testing, not regular scanning. You really should scan your systems without firewall interference to properly find and correct all vulnerabilities.
Hope this helps.
Regards,
-- Dan
Daniel Bowman Director of Support & QA Tenable Network Security mailto:[EMAIL PROTECTED]
----- Original Message ----- From: "Dave Tedder" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Thursday, March 10, 2005 3:09 PM
Subject: RE: Fw: Scan a firewall enabled system
How to scan a system on which firewall is enabled and ICMP is blocked?
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