nanog mailing list archives
Re: commonly blocked ISP ports
From: "Fergie (Paul Ferguson)" <fergdawg () netzero net>
Date: Wed, 14 Sep 2005 21:55:51 GMT
A couple of decent barometers: http://www.dshield.org/topports.php and: http://www.mynetwatchman.com/default.asp - ferg -- Luke Parrish <lukep () centurytel net> wrote: Not quite looking for tips to manage my network and ACL's or if should or should not be blocking, more looking for actual ports that other ISP's are blocking and why. For example: port 5 worm 2.5 port 67 virus 8.2 At 03:12 PM 9/14/2005, Valdis.Kletnieks () vt edu wrote:
On Wed, 14 Sep 2005 14:42:56 CDT, Luke Parrish said:We have a list, some reactive and some proactive, however we need toremoveports that are no longer a threat and add new ones as they are published.All ports that are open are threats, at least potentially. What you *should* be doing is: a) When you block a new port due to a current exploit, log the fact. b) Work with customers/users to make sure they're patched, and that new machines are patched before they go live. c) When probing for the port stops (which it never does), or some sufficient number of downstream boxes are patched and safe, remove the block. Either that, or block the world, and open ports on request. Remember - *you* are the only one on this list who really knows if a given port is a threat anymore.... (And that's totally skipping all the noise about corporate firewalls versus ISP firewalls and different expectations regarding security/transparency...)
Luke Parrish Centurytel Internet Operations 318-330-6661 -- "Fergie", a.k.a. Paul Ferguson Engineering Architecture for the Internet fergdawg () netzero net or fergdawg () sbcglobal net ferg's tech blog: http://fergdawg.blogspot.com/
Current thread:
- Re: commonly blocked ISP ports, (continued)
- Re: commonly blocked ISP ports Luke Parrish (Sep 14)
- Re: commonly blocked ISP ports Larry Smith (Sep 14)
- Re: commonly blocked ISP ports brett watson (Sep 14)
- Re: commonly blocked ISP ports Michael Tokarev (Sep 15)
- Re: commonly blocked ISP ports Jim Popovitch (Sep 15)
- Re: commonly blocked ISP ports Luke Parrish (Sep 14)
- Re: commonly blocked ISP ports Kim Onnel (Sep 15)
- Re: commonly blocked ISP ports Petri Helenius (Sep 15)
- Re: commonly blocked ISP ports John Kristoff (Sep 15)