Security Basics mailing list archives
RE: Which ports to block?
From: "Barber, Chris Mr. ATEC/Contractor" <Chris.M.Barber () atec army mil>
Date: Mon, 26 Jul 2004 15:05:40 -0400
Basically you would have a set of rules that would look similar to this Deny ICMP Any Any Allow from any to SMTP Server on port 25 Allow from InternalDNS to ExternalDNS on port 53 Allow from from InsideANY to OutsideANY on port 80 Deny Any Any This will do what you have stated below, but it may not do what you actually want. Firewalls can do many great things, including break your network if you are not careful. Make sure you do not close the door that lets you manage the firewall. Make sure that any inbound rules you put in place allow traffic only to a particular host and not the whole network. Chris. -----Original Message----- From: Ferino Mardo [mailto:RMardo () ALJOMAIHBEV com] Sent: Saturday, July 24, 2004 4:04 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. --------------------------------------------------------------------------- Ethical Hacking at the InfoSec Institute. Mention this ad and get $545 off 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. Visit us at: http://www.infosecinstitute.com/courses/ethical_hacking_training.html ---------------------------------------------------------------------------- --------------------------------------------------------------------------- Ethical Hacking at the InfoSec Institute. Mention this ad and get $545 off 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. Visit us at: http://www.infosecinstitute.com/courses/ethical_hacking_training.html ----------------------------------------------------------------------------
Current thread:
- Which ports to block? Ferino Mardo (Jul 26)
- Re: Which ports to block? mike (Jul 26)
- RE: Which ports to block? Ed Spencer (Jul 26)
- Re: Which ports to block? steve (Jul 26)
- Re: Which ports to block? VHP3 (Jul 27)
- <Possible follow-ups>
- RE: Which ports to block? Barber, Chris Mr. ATEC/Contractor (Jul 26)
- RE: Which ports to block? Hamish Stanaway (Jul 27)
- RE: Which ports to block? Ferino Mardo (Jul 27)
- RE: Which ports to block? Majed Mohammed Ayoub Al-Shodari (Jul 27)