I really don’t understand web hosting and all its terminology, but today I was considering a new VPS hosting service. The package includes two IPs. But I noticed that they advise you to use the same IP address for your primary and secondary nameservers, because “they are both on the same server”, so it would be a waste of an IP address.
In my experience (not much!), domain hosts require a different IP address for each name server, but my question really relates to having the secondary nameserver on the same server. Is this a problem? It seems pointless. Should I run for cover?
I’ve found that there are 3rd party providers, such as [noparse]www.afraid.org[/noparse], who allow you to set up a secondary, redundant name server, but I’d rather avoid that if possible, and I don’t really understand them anyway.
In my experience (not much!), domain hosts require a different IP address for each name server, but my question really relates to having the secondary nameserver on the same server. Is this a problem? It seems pointless. Should I run for cover?
Well, the two nameservers are supposed to give a level of redundancy. In practical terms, if all you’re going to host under this domain (including subdomains) will be hosted on this VPS, there will be little purpose to said redundancy. If the server as a whole is down, there’s virtually no benefit to DNS working properly. Having the DNS server that you operate on the VPS down, and everything else (web server, database server) working fine, is a very rare occurrence.
Many shared hosting providers use the same setup you have described (though not using the same IP for the two nameservers), and they have no problem because of it.
These are just personal opinions, I’m not all that technical either.
Thanks for that, ldcdc. I’ve read others say that it’s a terrible thing; but I wondered if, in practice, it’s such a big deal. The host is a pretty reputable one, so I’d think they’ve decided it’s not a big issue, but it’s nice to get some second opinions on it.
It is pretty common in the “single dedicated server” and VPS world. I have had to do this for some projects and have yet to (knock on wood) have an issue.
Thanks FFCus. Because I hadn’t heard of it before, I was a bit worried. But I’ve now realized that the VPS I had was probably doing it too. I just never realized. They didn’t tell me that, while the new host actually did tell me up front.
You can use an IP for more than one thing at once, however, nameservers on the same physical host isn’t always a good plan - if that server goes down, everything is gone… it is always advisable to use seperate machines for 2 dns servers “just incase”
Thanks guys. I guess if the nameserver is the same as the webserver, it’s also pointless to have a backup nameserver, as if the main nameserver is down, so will be the website.
It may surprise you to know that this, though commonly believed, is a Server Myth.
A second DNS server really only helps if you have DNS entries that point to services off-server. Email is queued on the sender for 4 days if your email server (and email DNS) is down; and your web services are down anyway. However, if you do have DNS entries referring to external services, a secondary DNS server will maintain access to those services. I’d include in this using 3rd party email services such as Google Apps; in that case, a secondary DNS server would keep your access to Google Apps up.
Secondary email servers are risky and I really don’t recommend them - they act as preferred entry points for spammers (ie more spam!), they can invisibly lose email if not configured correctly (and you will almost certainly not remember to test them), and they generally just make life messier. In the event of a real and prolonged disaster, you can usually add a secondary email server within 24 hours and you may want to take steps to ensure you are always able to do that.
