Making sense of DNS and Dynamic DNS?

I would just like to ask a question on the use of DNS, and my likelihood of
being able to make use of the service if I signed up...

Let me put you in the picture. I have had a .com domian now for a few
years, and although I have been offered DNS Management as an optional extra
on my domain, I have never signed up to it. The problem is, I don't realy
know if it would be of any use to me. I have read the information on their
website regarding DNS, and they say that using it, I can direct a URL, for
example 'myweb.mydomain.com' to an IP address of a computer.

Now my problem is, I have not got a fixed IP address and so everytime I lose
my connection, the IP address changes.

Because I have 'server assigned IP' I have been using No-IP for dynamic DNS
for a couple of year, to allow my computer to be located on the net.

My question is, if I sign up for DNS Management with my domain provider
(namezero), will I then be able to stop using No-IP, and rely entirely on
the service of namezero, or would I be better off carrying on using No-IP?

The namezero website, sort of suggests that I have to point to a IP address
manually, which would be a major problem if it wasn't updated automatically
when I lost a connection, as I would have to log into them everytime to
update the system with my new IP address...

My end aim is to set up my own mail server using my domain name, but I'm a
bit confused about the best way to do it.

NO-IP Dynamic DNS service has been excellent up to now and if required I
would upgrade from the free account I currently use, to a more powerful
option by paying a yearly fee, if it was going to benefit me with what I
want to do.

I would appreciate any help you might be able to offer on this...

Best Regards

Tony

 

[snip]

No-IP (and others offering similar services) are, as you'd expect,
specifically geared up for people in your position. As you mentioned, there
is software to update their DNS servers automatically - you probably won't
get that with your domain provider's DNS management.

Running your own mail server is not trivial - you really have to make sure
you understand how the server is configured, else you are likely to be
providing an open invitation to spammers. Which is a Bad Thing(tm).

Running a mail server on a dynamic address is possible but less preferable
than doing so with a static address. The problem - small but unavoidable -
is that whenever your address changes there is a window where new mail could
be scooped up by someone else.

Mail routing is controlled by MX records, which specify a name (*not* an
address) to forward mail to. If you want to run a mail server for
mydomain.com, you could use namezero's DNS management to add an MX record
for mydomain.com of "mysubdomain.no-ip.com." (or whatever it is), and run
the No-IP dynamic update client to keep the address associated with
mysubdomain.no-ip.com up to date.

Alex

 

Another problem is that quite a few mail exchanges will not accept mail
from dynamic addresses - there are blacklists for them similar to the
known open relay blacklists.

The reasoning is that a lot of viruses attempt to send mail directly, and
by blocking mail from dynamic addresses, much undesirable traffic can be
stopped. Virtually all ISPs provide "smart hosts" for their customers to
relay mail through, so it can be argued that it is never necessary to send
mail from a dynamic address.

So if you try to do this, you will probably find a fair proportion of your
mail getting rejected.

Regards, Ian

 

We are talking about receiving mail in not sending mail out? The OP
could always use a smart host for sending mail out, even though they
receive their mail direct to the box via the sender's MTA.

Andrew.

 

Yes that is right, however I would say at this point that there are a
lot of good registration providers out there, a lot now providing this
sort of functionalities by default/no extra cost.

If Namezero don't specify dynamic DNS then it won't be a good idea to
go with the namezero service. One thing you could do is to create
some DNS records in your namezero domain to point to the name of the
no-ip.com domain you own. This can be done easily with MX (mail
server) records, but if you want to do this with any other record
type, it won't work, and you would have to use a cname record, which
will cause the system to look up the IP of the pointed to record.

For example:

yourdomain.com has 2 MX records, the first going to
subdomain.no-ip.com, and a second provided by a backup server (for
when your server is offline).
www.yourdomain.com has a cname pointing to subdomain.no-ip.com.

There are posts on this topic regarding issues running mail servers
with a dynamic IP.

Or use cname/MX records in the way I showed you above, however, read
on...

You really need to get to grips with this before you start moving your
domain over to the new server, why not set up a mail server
temporairly for -ip.com?

Yes, that is the way I would probably go. No-ip can either host the
domain for you entirely, or you can just run the DNS for your domain
from no-ip. In the Namezero control panel, there will be a section to
enable/disable DNS management, and also to have the nameservers
delegated to another set of servers, which would be the no-ip.com
servers. You would then do all the DNS management (including dynamic
DNS on your domain) through no-ip.com.

Thanks.
Andrew.