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Re: Email tutorial?




On Tue, Apr 24, 2018 at 04:25:56PM -0400, mark@xxxxxxxxxxxx wrote:
> DHCP is like that, with an added twist:  When IP address change, in order for 
> you to get the e-mail an association between your IP-address and your physicla 
> computer, the change has to be broadcast to all the IP servers on the Internet 
> before you will be able to receive mail again.  That change can take days.

I know it's just an analogy, but this part is a bit misleading.  DNS
entries have a configurable "time to live" field, measured in seconds,
which tells caching DNS resolvers how long they're allowed to keep the
old addresses in memory before they have to check again for a changed
address record.

On a dynamic DNS setup meant for home users, the TTL is usually set
extremely low, like 60 seconds or 300 seconds.  It shouldn't take "days"
for an address change.

Also, DNS is not "broadcast to all IP servers".  Resolvers only ask
for the IP address records as needed.  At any given moment, only a
minuscule fraction of all the DNS resolvers in the world will have one
of your domain's records in memory, unless you are Google or YouTube
or Facebook.

> So, step 1 for you is to either spend the money on a static IP address or 
> check out one of the services that will show the Internet one IP address for 
> you, and will keep track of yours when it changes.  My expericence with those 
> is that you will, from time to time, lose e-mail.  If you are serious about 
> setting up a mail server, then complete step 1.

A third option is to rent a (virtual) server somewhere, and run your
email from there.  It will probably cost you a lot less than a static IP
address from your cable company (I don't actually know what Spectrum
charges for this, but it's probably more than $5 a month, and you can
certainly get a VPS at that price point).

Of course, there are drawbacks to all of these options, so you will have
to make your own decisions.