So if I set up my ISP's nameservers as forwarders on
my internal DNS server, what traffic do I need to
allow through my Checkpoint firewall?  What can I do
to make it as secure as possible?  My first thought
was to allow inbound & outbound UPD 53 only between my
internal DNS servers and the ISP's DNS servers.  I
disabled recursion on my internal DNS servers and I
obviously don't want zone transfers from outsiders. 
Any thoughts?
--- Paul Robertson <[EMAIL PROTECTED]> wrote:
> On Tue, 4 Dec 2001, Rick Brown wrote:
> 
> > This is a little off topic but I thought you guys
> > would be the one's to ask.  I only have a mail
> server
> > and a web server (for web-based email access) in
> my
> > DMZ.  Do I have to have a DNS server in the DMZ or
> can
> > I just use my ISP's DNS?  I have an internal DNS
> 
> To host DNS, or to resolve queries?
> 
> > server(s).  What are the drawbacks to using my
> ISP's
> > DNS.  I won't need to make very many DNS changes
> in
> 
> To resolve at the ISP:
> 
> Advantage- cache more likely to be populated.
>            security someone else's problem.
> 
> Disadvantage- security someone else's problem.
>               no control over cache/config.
> 
> To host at the ISP:
> 
> Advantage-    Probably better bandwidth.
>               Hopefully redundancy.
>               Less of a headache to administer.
> 
> Disadvantage- Emergency updates suck.
>               Scheduled updates suck too[1].
>               security someone else's problem (think
> ex-employee changes)
> 
> The end result is that I generally recommend a local
> caching-only
> nameserver to resolve queries for
> hosts/firewalls/desktops, and
> outsourcing hosting DNS unless you really need to
> manage the update
> process because of last-minute changes and have the
> appropriate multiple
> facilities/power/route infrastructure and the will
> to update BIND every
> week or so ;).
> 
> Your mail server should probably cache on itself
> anyway, delivery will be
> much more reliable and quick.
> 
> Paul
> [1] It's nice to be able to half the TTL for a while
> before a change until
> you get it down to 5m or whatever to actually make
> the change, then come
> back up with a low TTL to ensure you don't have to
> fall back.  Most ISPs
> have a TTL floor they won't go below.
>
-----------------------------------------------------------------------------
> Paul D. Robertson      "My statements in this
> message are personal opinions
> [EMAIL PROTECTED]      which may have no basis
> whatsoever in fact."
> 
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