email forwarding / dns question

PirateNinja

I have the following DNS setup:

MX 0 mydomain.com -> mail.mydomain.com
A mail.mydomain.com -> 10.10.10.10

Recently, my host of 10.10.10.10, changed my IP address without notifying me. All the email I had setup @ 10.10.10.10 broke. Actually I only use 10.10.10.10 for mail forwarding, but still it broke. Naturally I fixed it by changing this dns record:
A mail.mydomain.com -> 10.10.10.20

My questions:
1. Is there a good monitoring service you guys recommend that would SMS alert me the instant one of my forwarding email addresses stops working, whether it is a problem with DNS or otherwise?

2. Is there a better way for me to setup my DNS so that I can avoid downtime in the future?

3. Is there a good professional email forwarding only service out there? I see Dyn has one, but I'm hesitant.

troll

An MX record does not have to point to an IP Number.
Find out what name 10.10.10.20 resolves to.

So then you would have your "PirateNinja" domain setup at x.x.x.x usually points to you webserver...
and the MX record would be:

pirateninja.com. MX 0 mail.bigserverelsewhere.com.

make sure the periods are in place after the names. Otherwise the DNS tries to resolve to pirateninja.com.mail.bigserverelsewhere.com

BobbyDigi

But you still have to define mail.bigserverelsewhere.com specifically to an IP in the A record. There is no way around that. If your host doesn't tell you that the IP of the server changed, well, that is dick move on the host's side.

2. You may be able to get around that with DDNS

As for a notification when the email stops working, the only resolution my mind comes up with is an automated ping of the mail server and monitor the IP that resolves. If IP is different, send SMS.

Edit again because I reread OP questions.

RootWyrm

Arrrrgh. No. Just.. no.

1. Use Afraid.org (AKA FreeDNS) for dynamic DNS services. Just.. leave it at that. No muss, no fuss.
2. Don't go blaming DNS for your missing infrastructure. If you don't want email to go splat, have a backup MX. There's a reason we use a priority field in MX records and there's usually more than one.
3. There is no such thing as a good 'forwarding' service. Most intelligent servers out there will reject on A/PTR mismatch or missing PTR. Use hosting.

So what you should have is:
mydomain.int
SOA Section
IN MX 0 mail.mydomain.int
IN MX 10 mail2.mydomain.int
10.10.10.20 IN A mail.mydomain.int
10.10.10.21 IN A mail2.mydomain.int

10.10.10.in-addr.arpa
SOA Section
20 IN PTR mail.mydomain.int
21 IN PTR mail2.mydomain.int

BobbyDigi

Edit: Meh, I am in a mood. Ignore that.

PirateNinja

troll said:

An MX record does not have to point to an IP Number.
Find out what name 10.10.10.20 resolves to.

So then you would have your "PirateNinja" domain setup at x.x.x.x usually points to you webserver...
and the MX record would be:

pirateninja.com. MX 0 mail.bigserverelsewhere.com.

make sure the periods are in place after the names. Otherwise the DNS tries to resolve to pirateninja.com.mail.bigserverelsewhere.com

Pretty much, what @BobbyDigi said. If you look at my post I'm not pointing the MX record to an IP. It points to a domain, and the A record for that domain is what got butchered when the host of my mailserver didn't inform me of an IP change.
I still need the IP address for the A record, and the IP address is what changed on me a few days ago. Also this isn't for pirateninja.com, although by chance I do own that domain.

My DNS is hosted on a Route 53. My webserver and mail server are different. The mail server is a fully functional mail server, but it is only used for forwarding because I don't need it for anything else.

Essentially I'm asking for a recommendation for an excellent email only hosting company that won't change IPs without a heads up and a good service to monitor that mail server.

Rootwyrm ... thanks.
========

Anybody have other ideas to my original three questions?

troll

Sorry I misunderstood what @PirateNinja was trying to achieve, I thought he was just passing on SMTP traffic to a remote...

Here is a zone record for one of our customers from my DNS server at wrok. The names and IP's are munged as to not cause any issues.

Basically customers_domain.ca is his domain and his web and mail are hosted on not_my_server.ca.
We hosted his site and mail before but he required an exchange server so he moved his site and mail but left the DNS still with us...

In the following Zone record:

dns_server.at_work.ns.ca & second_dns_server.at_work.ns.ca are my DNS servers.
customers_domain.ca points to 209.xx.xx.139 which is the address of his website.
www.customers_domain.ca points to CNAME of 209.xx.xx.139
sharepoint.customers_domain.ca points to the sharepoint server at 209.xx.xx.141

Both MX records for his mail smtp1.not_my_server.ca & smtp2.not_my_server.ca do not have IP numbers, they just point to the FQDN of his hosts mail exchangers.

This way if his host ever changes mail exchanger IP numbers it does not matter as things will still resolve.

$ORIGIN .
$TTL 38400      ; 10 hours 40 minutes
customers_domain.ca		IN SOA  dns_server.at_work.ns.ca. hostmaster.at_work.ns.ca. (
                      1999999999 ; serial
                      10800      ; refresh (3 hours)
                      3600       ; retry (1 hour)
                      604800     ; expire (1 week)
                      38400      ; minimum (10 hours 40 minutes)
                      )
                      NS      dns_server.at_work.ns.ca.
                      NS      second_dns_server.at_work.ns.ca.
                      A       209.xx.xx.139
                      MX      0 smtp1.not_my_server.ca.
                      MX      10 smtp2.not_my_server.ca.
$ORIGIN customers_domain.ca.
sharepoint              A       209.xx.xx.141
www                     CNAME   redirect.not_my_server.ca.

Linc

I'm thinking a service like Pingdom could be used to watch it for uptime.