[ILUG] ADSL Trial and Dynamic DNS

[Dave Wilson]

> So, the question - would this work??


I think it will do what you expect it to, but I'm suspicious of using a 
dynamic host as a primary MX. If a remote site caches the address of 
your MX host for an extended period of time, and that address is 
allocated to another DSL customer in the meantime, then the remote site 
will attempt to deliver mail to that other customer. If they are running 
an SMTP server that denies relay, you will lose mail.

I think the above also applies if your DSL connection goes down for an 
extended period, and your old address is reallocated during the outage.

My instinct says there are better ways to do this, but I haven't got any 
to suggest in the general case :-( Personally, I'd use a colocated 
machine as my primary MX and update the mailertable and/or use another 
protocol to slurp the mail.


> Is it valid for one nameserver to point an MX record to a hostname whose A
> record is on another nameserver?


Yes, certainly.


> Does anyone reckon I'll have an issue with getting Eircom to change the MX
> record for me?


I can't say.


> Am I correct in thinking that this method will not involve IEDR in any way?


That's correct. Except for a very few records (I think it's about 
three), the .IE name servers only host NS records and glue records for 
subdomains.


Dave