Reverse NS lookup

[C.Krishna Prakash]

hi,

where the reverse NS lookup is exactly being used???

is there any docs' related abt the implemantion with clear examples....

Thanks.

[A. Clay Stephenson]

There is no way to answer your question exactly because the number of ways a reverse NS lookup are legion. A very common use is that used by the reshd daemon. Whenever a request comes in, a reverse lookup is done and then compared to the hostnames in .rhosts to see if a match is found.

[Kevin Wright]

many apps utilize reverse DNS lookups. Suggest you ensure your reverse zones are setup correctly.

[Bill Hassell]

It is very common for Windows admins to 'forget' reverse lookups, yet this is a very important method to authenticate an incoming IP address. For tools that bypass login/password such as the 'r' commands (remsh, rcp, rlogin, rexec) there is little the opsystem can do to make sure a hacker is not trying to break in. So the DNS server is consulted to see if both hostname and IP lookups work (and point to the same MAC address). The 'r' commands are by no means the only programs that use it. You may find that certain versions of database engines will validate connections with reverse checks. You can safely assume that there will be problems with a broken DNS server that does not provide reverse lookups (and MX records if you're going to use email).