Port Scanning

[regrettableerror at netscape.net (Regrettable Error)]

"Chuck Young" <chy at genuity.com> wrote:

>I'm not sure about sending mail to RegrettableError at netscape.net
>
>Bill is that your email address?

It is. I use for posting to "public" places so as to avoid tiresome disclaimers as to my lack of authority when posting from work. I also use a hotmail address from time to time; same reason. The hotmail/netscape is also convenient to check my mail (which is auto-forwarded with a cron job) when I'm at school.

>
>Anyway, the answer(s) depend on the scan type and firewall you are running.
>What will your firewall do if I send a TCP SYN or UDP packet or ICMP message
>to an unserved port?

It will accept SYN packets to ports 25, 53, 67, and 80. All others are rejected with an error message unless they're associated with an existing connection.

It uses IPTABLES.

Bill

>
>---------------
>Chuck Young
>Security Consulting
>Genuity E-Services
>--------------------
>
>-----Original Message-----
>From: discuss-admin at blu.org [mailto:discuss-admin at blu.org]On Behalf Of
>Regrettable Error
>Sent: Monday, December 10, 2001 8:34 PM
>To: discuss at blu.org
>Subject: Port Scanning
>
>
>Thanks for reading this. Sorry if it's a dup: Netscape just crashed when I
>tried to send it before.
>
>I'm curious about port-scanning, and have a question. Suppose someone is
>trying to find a hole in my firewall, and scans a port that I'm not
>running. Won't their scan come up "negative" for that port?
>
>TIA.
>
>Bill Horne


-- 
--
RegrettableError



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