Complex DNS question. Does DNS introduce latency in high bandwidth apps?

Currently we have about 30 machines that connect to our site over (2) 10Mbps lines.
I'm looking into getting a 3rd line but that is another issue.

Right now, all the clients connect to us strictly by IP address. We've had some issues in the past where our IP had to change and I want to never be caught in that situation again.

SO.. I want to try and move the sites to instead connect to us through a DNS subdomain IE wan1.company.com , wan2.company.com

The only issue I have is, I am worried that introducing a DNS scheme like this will add latency to the connection (some sites are oversees and this would be unacceptable)
Along with, what if the company, lets say godaddy, that is handling our DNS goes down or somehow becomes unresponsive. Are clients no longer able to connect?

is the DNS server located on the same site as the other servers?

I COULD manage them, but then I'd have to buy seperate servers to run and introduce unecessary cost.

I would prefer to just have a registrar like godaddy or network solutions manage the DNS. That is why I'm concered. If someone like them manages it, will it introduce latency and be saceptable to their outages.

Typically the DNS lookup only happens once at the beginning of the connection. Windows also typically caches DNS for 24 hours, but this can be manually cleared(ipconfig /flushdns) or you can set the timers to a lower setting. I wouldn’t worry about latency, except maybe a few Milliseconds at the beginning of a session.

Another thing is DNS propagation. If your IP address changes it can take days for it to propagate to all the DNS servers. (I have seen 3 days quoted as an average number, but in reality it's variable depending on provider.)

DNS servers are handled by each individuals provider typically, unless they specify other DNS servers, or have their own.

How easy is it to get these clients to make changes on their systems? Maybe you could run your own DNS server and have them point to it as an additional DNS server?

There are companies who can manage proper DNS for you. GoDaddy probably does not qualify as a proper DNS provider.

If you are worried about DNS propagation time, if you manage your own DNS or have a service that allows you to change your TTL, you can set how long your DNS responses to be valid.

It is best to have your own DNS server, as it gives you unlimited control.

Eickst said:

There are companies who can manage proper DNS for you. GoDaddy probably does not qualify as a proper DNS provider.

Click to expand...

who is.

Name resolution is really very quick. Once the DNS info has propagated (usually a couple days, I've never seen it take longer than 6 and that was with a poor provider) the actual lookup time only occurs once at the very beginning, before the initial connection is established, and then it doesn't really happen again.

No matter how complicated your DNS schema is (assuming you're not doing all sort of weirdness), ultimately only the first authoritative response will be used, so latency will not be an issue.

There are, however, situations where DNS schema can be a severe problem, but you only see these issues internally, and when you manage your own DNS servers, and when the previous retard network admins happened to give your domain a ".com" FQDN.

so, in short, DNS shoudn't cause any latency.

::EDIT:: A couple more answers to your questions: Assuming you choose a quality provider, www.prohosting.com comes to mind, there won't be any issues with outages and whatnot. A proper registrar will make sure that the DNS info is always available, and you will always have the ability to change the info whenever you want.

There are alot of seed DNS servers that control name resolution. ISP's have their own, registrars for domain names have their own, there are a couple that are around that do nothing but offer backup support....so, essentially, once your info has spread around a bit, even if your registrar goes down or stops responding to requests, you should still be able to access your site via FQDN without issue. The only time provider issues will effect this is if you change the DNS entries and they are slow to update. Once it's out there, it's out there.

I would say that its best to manage your own DNS as it gives you all the controll you will need.

DNS will add latency to the initial look up but it will be so small you will never notice.

Eickst said:

There are companies who can manage proper DNS for you. GoDaddy probably does not qualify as a proper DNS provider.

If you are worried about DNS propagation time, if you manage your own DNS or have a service that allows you to change your TTL, you can set how long your DNS responses to be valid.

It is best to have your own DNS server, as it gives you unlimited control.

Click to expand...

GODADDY actually has excellent DNS service. They support all record types (including custom service records) through an easy to use web interface, and you have individual control on each record including the TTL time which you can set from weeks down to a half-hour.

Eickst said:

There are companies who can manage proper DNS for you. GoDaddy probably does not qualify as a proper DNS provider.

If you are worried about DNS propagation time, if you manage your own DNS or have a service that allows you to change your TTL, you can set how long your DNS responses to be valid.

It is best to have your own DNS server, as it gives you unlimited control.

Click to expand...

GODADDY actually has excellent DNS service. They support all record types (including custom service records) through an easy to use web interface, and you have individual control on each record including the TTL time which you can set from weeks down to a half-hour. They've just added a new feature in the past couple of days where you can copy host names between zones if you want the same host names in multiple zones.

moetop said:

Typically the DNS lookup only happens once at the beginning of the connection. Windows also typically caches DNS for 24 hours, but this can be manually cleared(ipconfig /flushdns) or you can set the timers to a lower setting.

Click to expand...

Actually, Windows caches the record for its TTL time value as supplied in its DNS query or 24 hours, whichever is shorter.

I use 1 hour TTL values on my records at Godaddy, and change the TTL to a half-hour a few days ahead of an anticipated change. At any location using well behaved DNS servers for name resolution (they actually pay attention to TTL values), any change I have made has been in place within 2 hours Internet wide. There are a lot of DNS servers that are badly behaved on the Internet, so always plan for 24 hours, just to be on the safe side.

Hmm, I guess GoDaddy must have improved their DNS service since the last time I looked at it. They used to not give that kind of control over the records, it was pretty basic. But, I do my own DNS so I haven't had to look at their offerings for years.