Ethical Hacking Learn to find vulnerabilities before the bad guys do! Gain real world hands on hacking experience in our state of the art hacking lab. Course designed and taught by expert instructors with years of penetration testing experience. 12 student maximum in every class. Certification attempt included in every package. | Computer Forensics Training at InfoSec Institute Gain the in-demand skills of a certified computer examiner, learn to recover trace data left behind by fraud, theft, and cybercrime perpetrators. Discover the source of computer crime and abuse at your organization so that it never happens again. All of our class sizes are guaranteed to be 12 students or less to facilitate one-on-one interaction with one of our expert instructors. |

| Subject: | Re: DNS ACL ? |
|---|---|
| Date: | Sat, 12 Nov 2005 11:23:23 -0700 |
On 11/11/05, John Hally <JHally@epnet.com> wrote:
Hello All, I need a sanity check regarding DNS ACLs. For external facing DNS servers you need to allow only udp/53 inbound, correct? I know tcp/53 is used for zone transfers and requests/replies greater than a certain size, but they shouldn't typically happen for general dns queries correct?
I think that the backbone DNS servers and certain upstream DNS servers require TCP, and if for some reason a query can not fit into a single UDP packet it will switch to TCP. So if you do not have insane hostnames or extra info (long TXT sections etc), then TCP would not be needed to the world.. locking it down so that it only talks to known upstream boxes would probably be correct. -- Stephen J Smoogen. CSIRT/Linux System Administrator ------------------------------------------------------------------------------ Audit your website security with Acunetix Web Vulnerability Scanner: Hackers are concentrating their efforts on attacking applications on your website. Up to 75% of cyber attacks are launched on shopping carts, forms, login pages, dynamic content etc. Firewalls, SSL and locked-down servers are futile against web application hacking. Check your website for vulnerabilities to SQL injection, Cross site scripting and other web attacks before hackers do! Download Trial at: http://www.securityfocus.com/sponsor/pen-test_050831 -------------------------------------------------------------------------------
| <Prev in Thread] | Current Thread | [Next in Thread> |
|---|---|---|
| ||
| Previous by Date: | Re: DNS ACL ?, John Nemeth |
|---|---|
| Next by Date: | RE: DNS ACL ?, Maher Odeh |
| Previous by Thread: | DNS ACL ?, John Hally |
| Next by Thread: | RE: DNS ACL ?, Jason Muskat |
| Indexes: | [Date] [Thread] [Top] [All Lists] |