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Gaybucks · 04-04-2006, 03:13 PM

Not trying to discount your points, or to say that your investment isn't justified as an additional bulletproofing of your affiliate program... I'm a strong believer in building the most robust infrastructure possible, but I also don't like to see people grossly overselling their product, and for the most part, that's what UltraDNS is doing in my opinion.

I congratulate you on being willing to spend the money to come up with the most robust solution possible for your affiliates and customers, because too many sponsors simply go for the lowest cost solution, and then wonder why they have retention problems or conversion problems... I just don't like to see people get hosed with technical mumbo-jumbo, and it feels like that's exactly what UltraDNS salespoeple are doing.

I'm just saying that buying geographically diverse DNS is probably unnecessary overkill, because the likelihood of actually missing a hit *because of DNS* is extremely remote, given that probably 95%+ of DNS hits for your site won't even *be* to your DNS, whether it's UltraDNS or your server's upstream ISP...

For example, if you are Pornsite B, and Joe Pornviewer clicks on pornsite A and pornsite B at the same time, and A happens to have been clicked on by Bill Pornviewer (who uses the same broadband provider) an hour ago, but for some reason, no one from that broadband provider has clicked on pornsite B in the last 6 hours, no matter *WHOSE* DNS you use, there will be a much longer delay in retrieving the correct DNS for pornsite B than pornsite A. Why? Because A is in the local ISP cache of the broadband provider, while B is not.

Regardless of who you use for DNS, Joe Pornviewer's local DNS, run by his broadband provider, is the first point of contact. The local DNS has to look and see if it has an entry in cache BEFORE it sends the request out to the authoritative DNS for that domain. The time to look it up in local cache isn't insignificant, and often takes FAR longer (100-300ms isn't uncommon, depending on cache size and DNS load) than the actual request and response from the authoritative DNS.

So in your scenario, if the difference in a join is in that 100-300ms difference in DNS response time, then Pornsite A is going to get the join, and he's probably using his ISP's free DNS. The only way to prevent that from happening and ensure a short response time would be to put a computer with an automated refresh of your site on the network of every major ISP worldwide, and ensure that it requests the IP address of your site from its local DNS more often than whatever the time-to-live setting is for your domain in DNS settings. Having a DNS node that is 5 ms away from the DNS used by the broadband provider won't make a whit of difference if your site isn't in cache for that provider... it will STILL take up to a couple hundred milliseconds for the cache lookup to fail, the broadband DNS to contract the root nameservers to find out what DNS is responsible for that domain, and then to contact UltraDNS and get a response.

I am guessing that most of the salespeople selling UltraDNS probably have no idea how DNS actually works, except at the most basic level. It's a complex beast with dozens of variables that affect caching time, refresh of mirror DNS, the order in which primary, secondary, and tertiary DNS are contacted, and so forth. I don't claim to be a DNS guru, but I know a little about it because I've had to troubleshoot DNS problems for customers that hosted with the ISP that I used to run, and I've unfortunately found that my knowledge of DNS is often more complete (as minimal as it is) than the techs responsible for maintaining DNS as many ISPs.

There's tons of redundancy inherently built into the Net's DNS structure, and the architecture was designed *specifically* to minimize DNS traffic and hits to the authoritative DNS (in this case UltraDNS), so the DNS system is not nearly as "unreliable" as UltraDNS would have you believe, unless your particular ISP is not following the applicable RFC when installing and running its DNS servers.

04-04-2006, 03:13 PM
Gaybucks Confirmed User Join Date: May 2004 Location: Sacramento, CA Posts: 451	Not trying to discount your points, or to say that your investment isn't justified as an additional bulletproofing of your affiliate program... I'm a strong believer in building the most robust infrastructure possible, but I also don't like to see people grossly overselling their product, and for the most part, that's what UltraDNS is doing in my opinion. I congratulate you on being willing to spend the money to come up with the most robust solution possible for your affiliates and customers, because too many sponsors simply go for the lowest cost solution, and then wonder why they have retention problems or conversion problems... I just don't like to see people get hosed with technical mumbo-jumbo, and it feels like that's exactly what UltraDNS salespoeple are doing. I'm just saying that buying geographically diverse DNS is probably unnecessary overkill, because the likelihood of actually missing a hit because of DNS is extremely remote, given that probably 95%+ of DNS hits for your site won't even be to your DNS, whether it's UltraDNS or your server's upstream ISP... For example, if you are Pornsite B, and Joe Pornviewer clicks on pornsite A and pornsite B at the same time, and A happens to have been clicked on by Bill Pornviewer (who uses the same broadband provider) an hour ago, but for some reason, no one from that broadband provider has clicked on pornsite B in the last 6 hours, no matter WHOSE DNS you use, there will be a much longer delay in retrieving the correct DNS for pornsite B than pornsite A. Why? Because A is in the local ISP cache of the broadband provider, while B is not. Regardless of who you use for DNS, Joe Pornviewer's local DNS, run by his broadband provider, is the first point of contact. The local DNS has to look and see if it has an entry in cache BEFORE it sends the request out to the authoritative DNS for that domain. The time to look it up in local cache isn't insignificant, and often takes FAR longer (100-300ms isn't uncommon, depending on cache size and DNS load) than the actual request and response from the authoritative DNS. So in your scenario, if the difference in a join is in that 100-300ms difference in DNS response time, then Pornsite A is going to get the join, and he's probably using his ISP's free DNS. The only way to prevent that from happening and ensure a short response time would be to put a computer with an automated refresh of your site on the network of every major ISP worldwide, and ensure that it requests the IP address of your site from its local DNS more often than whatever the time-to-live setting is for your domain in DNS settings. Having a DNS node that is 5 ms away from the DNS used by the broadband provider won't make a whit of difference if your site isn't in cache for that provider... it will STILL take up to a couple hundred milliseconds for the cache lookup to fail, the broadband DNS to contract the root nameservers to find out what DNS is responsible for that domain, and then to contact UltraDNS and get a response. I am guessing that most of the salespeople selling UltraDNS probably have no idea how DNS actually works, except at the most basic level. It's a complex beast with dozens of variables that affect caching time, refresh of mirror DNS, the order in which primary, secondary, and tertiary DNS are contacted, and so forth. I don't claim to be a DNS guru, but I know a little about it because I've had to troubleshoot DNS problems for customers that hosted with the ISP that I used to run, and I've unfortunately found that my knowledge of DNS is often more complete (as minimal as it is) than the techs responsible for maintaining DNS as many ISPs. There's tons of redundancy inherently built into the Net's DNS structure, and the architecture was designed specifically to minimize DNS traffic and hits to the authoritative DNS (in this case UltraDNS), so the DNS system is not nearly as "unreliable" as UltraDNS would have you believe, unless your particular ISP is not following the applicable RFC when installing and running its DNS servers. __________________ Gaybucks.com 100% exclusive American guys - hosted movie galleries - NATS - Boyfunk.com - Boysfeetclub.com - AJsCloset.com- SkylerDeVoss.com ICQ 272-995-402