[NTLUG:Discuss] Dynamic IP and External DNS - is it possible?

David Stanaway david at stanaway.net
Thu Oct 25 18:54:51 CDT 2007


It would be cheaper for you to set up a virtual system at one of the 
places mentioned in the recent hosting threads. That should have a 
static IP and allow you to install whatever flavor of DNS server (Bind9 
for instance - there are others).

YOu can then have your home pc register dynamically with that through 
bind dynamic dns or through some other mechanism and have your virtual 
server either be a secondary MX for your domain for when your primary 
goes down.

The prob with using dynamic IP for your mailserver is that:
  - dynamic ranges can tend to be blocked in rbls
  - you don't control the PTR records for your IP and this is not 
'correct' for an MX record which should be a canonical name  with 
consistent PTR record.
  - If your IP changes and someone else gets your IP, then they will get 
(And hopefully bounce) your email. Makes your domain look unreliable 
(Because it is).



Keller Giacomarro wrote:
> Chris Cox wrote:
>> Keller Giacomarro wrote:
>>   
>>> This is something of a Linux question, since I'm implementing it in Linux -
>>> please let me know if this type of query is inappropriate for this list.
>>>
>>> Being the student of networking that I am, I've recently gotten very
>>> interested in DNS.  To learn more, I'd like to set up an external DNS server
>>> for my personal domain.  Here's what's setup now:
>>>
>>> kellerg.com points to my RoadRunner cable IP address.  I'm using
>>> no-ip.comto accomplish this.
>>> Everytime my IP changes, no-ip updates its DNS A record for kellerg.com with
>>> my current IP.
>>>
>>> What I want to have happen is DNS requests for my domain should come to my
>>> bind9 DNS server.  I know that I can just add CNAME and MX records with
>>> No-IP, but I really just want no-ip to resolve kellerg.com and then pass
>>> everything else to my nameserver.
>>>
>>> No-IP says this isn't possible without a static IP.  Is that true?
>>>     
>> You have to register your nameservers (IPs) as being authoritative for
>> your domain (zone) so that when people want to query your records, they can.
>> So... yes... you need a static IP for your nameservers (and you really
>> should have more than one).
>>
>> With that said.... friends and family CAN use you as THEIR nameserver.
>> Thus in the their resolv.conf they would have:
>>
>> nameserver <your-ip-address>
>>
>> Of course, you can then be authoritative for ALL domains... AND you'll
>> need to handle recursive queries (if people find out about your little
>> nameserver they may ALL try to use it). They could also run their
>> own DNS servers which are mostly caching and delegate records out to
>> your nameserver for your domain (zone)... or even forward to it.
>> But obviously not as ideal as having a TRUE domain nameserver
>> with a registered static IP(s) associated with your domain (zone).
>>
>>
>> _______________________________________________
>> http://www.ntlug.org/mailman/listinfo/discuss
>>   
> Chris,
> 
> Thank you for not only the answer to my question, but some cool ideas 
> for things I can do with DNS until I can afford to pay the extra per 
> month for static IPs!
> 
> On that note, is anyone aware of quick (6Mbps down, 256k up or faster) 
> DSL or cable service that provides static IPs and is reasonably priced?  
> Thanks again. =)
> 
> -Keller
> 
> _______________________________________________
> http://www.ntlug.org/mailman/listinfo/discuss
> 




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