DNS update

[Barry Margolin]

In article <VonP4.34415$Xk2.126959 at tor-nn1.netcom.ca>,
T-bag <tbag at fastmail.com> wrote:
>> But if you're talking about *reverse* DNS, that requires the cooperation
>of
>> your ISP.
>
>What is the difference between forward and reverse .. why is reverse needed?

Forward translates names to addresses, reverse translates addresses to
names.

If you have a firewall on your computer and you look at its logs, and
wondered "who are all these machines scanning me?" you can understand why
reverse is needed.

>But it's generally not critical that the reverse DNS entry match
>> your forward entry.  The ISP should have a name in their own domain that
>> also maps to your address, and that's sufficient.  There's nothing wrong
>> with having two A records point to the same IP address, and the PTR record
>> only needs to point to one of them.
>>
>
>But the default one would be the ISP's?  For example for an hostname to work
>on irc would you need reverse?

Right, the reverse DNS would normally point to a name in the ISP's domain,
something pretty meaningless like customer-1234.isp.net.

But if you want to host an IRC, that should't be a problem.  You can have
a hostname in your own domain that points to your address.  When someone
wants to connect, they look up the name in forward DNS, get the address,
and then connect to that address; reverse DNS is not involved.

-- 
Barry Margolin, barmar at genuity.net
Genuity, Burlington, MA
*** DON'T SEND TECHNICAL QUESTIONS DIRECTLY TO ME, post them to newsgroups.
Please DON'T copy followups to me -- I'll assume it wasn't posted to the group.