Re: A simple script to update dynamic dns name record

From: jpd (read_the_sig_at_do.not.spam.it.invalid)
Date: 09/28/05 

Date: 28 Sep 2005 13:22:19 GMT

Begin <6jrp03-scq2.ln1@cnzhijiao.com>
On 2005-09-28, Sunry Chen <sunrychen@gmail.com> wrote:
[problem]
[unrelated solution]
> Finally I found the real couse is that my box has no MX record, why can't
> I just use a free dynamic dns name to have my own MX record?

There's no reason why you can't, except maybe that it depends on someone
offering this service for free to you. Why should they?[0]

Anyway, back to your real problem: Even with an MX lots of MTAs will not
accept your mail if you are from a ``known'' dialin ip, whether or not
you have an actual mx record. The thing to check for is to have a) valid
reverse[1] and ideally also have b) matching forward and reverse records.
Another thing is that you might end up in tainted netblocks and then no
amount of reverse and forward matching will help.

The way to get mail in a reliable fashion off your mobile box is to have
another machine somewhere[2] that will accept mail from you after you've
authenticated, and then sends it on to the destination. This can be done
with a variety of MTAs on your own box.

[0] Even if you can find such a someone, this is still a good question.
[1] That is, there exists for the IP you're using a PTR record, preferably
    one that does NOT say ``<ip>.dialin.dynamic-pool.provider.com'', because
    to many a mail operator that implies ``should not originate email''.
[2] Either operated by you, possibly co-located somewhere, or a paid-for
    service with a reputable mail provider. 

-- 
  j p d (at) d s b (dot) t u d e l f t (dot) n l .