Correct DNS records?

I am playing with running my own DNS server on my Linode. I got GoDaddy.com to point to my IP address using their "Domain Host Summary" function. I then setup PowerDNS (I want to be able to edit my DNS records in a MySQL database) with the records that I think should exists. It all seems to work, but it seems MUCH slower to connect. I can ssh to my Linode with the IP address and it connects in about 7 seconds. If I try connecting via my domain name then it takes about 20 seconds to connect. I am wondering if I have something setup wrong? I would think my ISP would cache the DNS lookup so it would be fast (except for maybe the first time it did a lookup).

The domain is realsimplehosting.com. The following is are my DNS records:

+-------------------------+------+------------------------------------------+-------+------+
| name                    | type | content                                  | ttl   | prio |
+-------------------------+------+------------------------------------------+-------+------+
| realsimplehosting.com   | SOA  | primary hostmaster@realsimplehosting.com | 86400 | NULL |
| realsimplehosting.com   | NS   | ns1.realsimplehosting.com                | 86400 | NULL |
| realsimplehosting.com   | NS   | ns2.realsimplehosting.com                | 86400 | NULL |
| realsimplehosting.com   | MX   | mail.realsimplehosting.com               | 86400 |    1 |
| realsimplehosting.com   | A    | 66.220.1.98                              | 86400 | NULL |
| 66.220.1.98             | PTR  | realsimplehosting.com                    | 86400 | NULL |
| *.realsimplehosting.com | A    | 66.220.1.98                              | 86400 | NULL |
+-------------------------+------+------------------------------------------+-------+------+

Looking at this I would think that I can drop the PTR record since people do reverse DNS for my IP end up getting the answer from Linode. Also I am not sure about both A records. Can I just have the wildcard record and have everything work (including just "realsimplehosting.com")? Also do I need the NS records? Don't people get that from GoDaddy. Basically I am thinking that I all need are the SOA, wildcard A, and MX record. Is this correct or should I leave all the records. I am afraid my knowledge on DNS is limited.

Thanks for any pointer yall can give.

3 Replies

You are mostly correct.

You can drop the PTR records. You CAN have a wildcard A record. The records you need to keep are:

SOA

NS

A wildcard.

> Don't people get that from GoDaddy

Nope. Once DNS is pointed to you all DNS is pointed to you. Of course, having only one DNS server means that if your linode dies, DNS dies with it. Since everything is on the same machine, that may not be a problem becasue DNS is pretty useless if all the services it points to are down.

The PTR will do nothing. Chris controls the server that is reverse-authoritative for the linode IPs. I believe that it's possible to point authority for each IP address to different DNS hosts, but it's not really worth it. It just adds one more layer of complexity.

As for slow queries, how is the DNS server started? If it's starting as a service that runs on it's own, I don't know what to tell you. If it's started by something like inetd each time there's a query, the startup time would explain the lag. In that case I'd say figure out how to start it as a service.

One more thing. Given your domain name I'm guessing that you'll be running a hosting service off your linode. Might I suggest that you'd be well advised to get a second linode (preferably in the other datacenter) that mirrors the current one for failover purposes. People don't like when something happens to their precious web sites. Just a thought.

–James

@irgeek:

Nope. Once DNS is pointed to you all DNS is pointed to you. Of course, having only one DNS server means that if your linode dies, DNS dies with it. Since everything is on the same machine, that may not be a problem becasue DNS is pretty useless if all the services it points to are down.

Yea for right now that is my thought. DNS does no good if the service is not running.

@irgeek:

As for slow queries, how is the DNS server started? If it's starting as a service that runs on it's own, I don't know what to tell you. If it's started by something like inetd each time there's a query, the startup time would explain the lag. In that case I'd say figure out how to start it as a service.

I figured it out. It has something to do with my home setup. Either it is not getting cached by my ISP or my ISP is real slow. I pointed my resolv.conf to my DNS server and it goes fast. So I know my server is responding quickly. I have also tested at other locations and it resolves quickly.

> One more thing. Given your domain name I'm guessing that you'll be running a hosting service off your linode. Might I suggest that you'd be well advised to get a second linode (preferably in the other datacenter) that mirrors the current one for failover purposes. People don't like when something happens to their precious web sites. Just a thought.

Yea I am just kind of getting started now. I have 4 sites that I was hosting on phpWebhosting for $10 per month. phpWebhosting was good to me but I wanted more control. I saw I could get a linode for $20 per month and have my own server. I figured I could get more control and save $20. If I get enough people I will start adding some redundency but right now it provides "enough" reliability for the people I am hosting. In the end it is just something on the side. Not really a "real" webhosting company (yet). The people I host know this and accept this.

Thanks for your help and advice.

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