RE: Which ports to block?

["Ed Spencer" <espencer () usa net>]

It's safest to block thru 65535.  There are many services that run above
1023 and these would be allowed through the firewall if you don't block
them (depending on the firewall and implementation).  Remember just
because they're not 'well-known' doesn't mean that they're not
well-known. ;-)

Ed Spencer
MCSE/MCT/MCP/CNA/A+/Network+/Security+
Network Administrator
Aramark Corporation
Denali National Park.

-----Original Message-----
From: Ferino Mardo [mailto:RMardo () ALJOMAIHBEV com] 
Sent: Saturday, July 24, 2004 12:04 AM
To: security-basics () securityfocus com
Subject: Which ports to block?

In setting up a "deny all" rule from a firewall, is it safe to block
ports 0 to 65535 or only up to 1023? My interest are only to allow port
53 udp, 25, and 80.

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any course! All of our class sizes are guaranteed to be 10 students or less 
to facilitate one-on-one interaction with one of our expert instructors. 
Attend a course taught by an expert instructor with years of in-the-field 
pen testing experience in our state of the art hacking lab. Master the skills 
of an Ethical Hacker to better assess the security of your organization. 
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