DNS OSI Layer

CISSPGOAL

Hi,

Is DNS reside in Session Layer or Application Layer?

Thank You.

goktan

Hi,
Although I've seen some debates about this, I believe the correct answer should be Application layer for the exam. Also wikipedia says so;
List of network protocols (OSI model) - Wikipedia, the free encyclopedia

Moreover, I've found similar discussion on this forum happened years ago, check if you want to see what others said then;
http://www.techexams.net/forums/network/15033-osi-layer-dns.html

hope this helps,
goktan

mochaaddict

I have always known dns to be layer 7. What rationale do you have to think it may be a session layer protocol?

Justin-

Application layer. I agree with the user above. Why you think it's session?

CISSPGOAL

Saw CISSP Notes that say it is a session layer .

tchoki

Session layer as with all directory services such as LDAP , X.500 . Also radius, tacacs+ , diameter, SMB , CIFS,NIS, NFS, SQL,RPC,Netbios, all work at the session layer . ISC2 says it clearly in its seminar book.

JDMurray

DNS really does not use session control. The 53/udp function is just a call and response with no preserved state information. The 53/tcp function is basically a file information transfer, like FTP, that uses one TCP connection per transfer. If DNS could do multiple, independent, simultaneous zone transfers over a single TCP connection then I'd say DNS used the OSI session layer.

papadoc

One of the things I learned from the SANS MGT414 course was they teach you how to think in the "ISC2" world. I would go with what tchoki said --the ISC2 - Official Guide to the CBK - Third Edition.