problem with reverse lookup of private IP

[phn at icke-reklam.ipsec.nu]

Sally Wong <sywong10 at yahoo.com> wrote:

> Hi,

> we have had problem to ftp or to telnet from PC that uses a private
> IP.  We use to have this problem intermittently, and this consistently
> happens to the PC with a private IP.  There is no problem when coming
> from a public IP.  Our DNS server crashed last week, ever since it
> came back on, we have heard a lot more of such kind of problem.

> However, sometimes if we added the private IP address into the
> /etc/hosts file, this problem would go away.  Looks to me this is a
> reverse lookup kind of problem.  Do anybody out there know of such a
> case?

The private (aka rfc1918  ) addresses is not resolved on internet, thus 
they will "time out" before a nameserver gives up. This takes time, 
and this is what you observe as delays.

To prevent this you should create a "reverse zone" for all the 1918 addresses
you expect to happen, and make shure that any query for "PTR" will reach
a servers that at least has the zone.

Typically this will be done in your "outermost" nameservers.

> many thanks

> Sally

> does anybody know if any strange things happen when rfc1918 is in the
> picture?


-- 
Peter Håkanson         
        IPSec  Sverige      (At the Riverside of Gothenburg, home of Volvo)
           Sorry about my e-mail address, but i'm trying to keep spam out.
	   Remove "icke-reklam" and it works.