Our ISP says they can't restrict zone transfers

[William Bell]

Hi,
First, it¹s been a few years since I maintained BIND servers, so please
forgive my rustiness.  :)
I couldn¹t¹ find an answer to this particular question in the archives, soŠ
What valid reason would any ISP or DNS hosting company have for NOT
restricting zone transfers to valid nameservers, IP¹s, hosts, etc?

Also, a ³zone transfer² and an AXFR request are the same thing aren¹t they?

Why I¹m asking this question:
We recently determined that our ISP/DNS host  (Time Warner Telecom) allows
zone transfers for our domains from anywhere on the internet (as far as we
can tell).  So I called and asked them to restrict zone transfers for our
domains to their own DNS servers and to our internet IP blocks.  Sounds like
a simple ³allow-transfer² directive in our zone file, right?  Not according
to the TW rep I spoke to.  They told me that, since they were the
authoritative DNS servers for our domains, if they restricted zone transfers
as I requested, then no one would be able to access our DNS and thus no one
would be able to access our servers from the internet.  Okay, it¹s been 4 or
5 years since I¹ve done any DNS work, but this response struck me as a bit
strange.  I began to suspect that either I was much less informed about DNS
than this Time Warner rep or vice versa.

In addition, during the course of the conversation, she also stated with
conviction that zone transfers and AXFR¹s were 2 different things.  I was so
dumbfounded that I that I didn¹t know what to say.  Again, I gave her the
benefit of the doubt; I considered that maybe I had been somehow misinformed
all these years or that the DNS paradigm had changed ‹ after all this was a
³level 2² person in the DNS group at Time Warner ‹ so I let it go.   I just
thanked her for her time, asked her to keep the ticket open and told her I
would get back to them.

I should¹ve just escalated, but I started this call believing that I was
making a simple request; I wasn¹t prepared for a battle.  So I quickly
decided that my best tactic was to retreat, regroup, and attack with more
troops from a different direction.  Hence this email.  Besides, I wasn¹t
sure that I wanted someone who didn¹t quite grasp these concepts making
changes to our zone files.

I realize that restricting zone transfers is a minor security enhancement,
but every little bit helps.  Besides, my boss told me to get it done.  ;)

Any advice would be greatly appreciated.
Thanks

-- 
Regards,
Bill

"No trees were killed in the making of this e-mail... however,
a large number of electrons were terribly inconvenienced."