May be you can teach me more.... this is a interesting tread..
You show that yahoo and google only allow to store a resolving in cache for max. 5 mins. if I understand well?
But when I look in my cache of my main gateway, (which is my root cache server) I see hundreds of name translations being cached.
[Two types though, type ¨A¨ and typy ¨CNAME¨. I don't know exact the difference but that's another question actually.]
But the point is that most of the translations carry a TTL of many days and counting down. The most is almost 7 days meaning in my opinion most of the translations stay in cache for 7 days?
You show that ¨Akamai.com¨ only allows their translation being solved for 20 secs. Why is this that short? Do they swap IP's that often? I can understand that big servers like google and yahoo might have reasons to work with several IP's for their servers so the dns has to be kept updated as much as possible.
But Akamai? Why would they want you to update your cache every 20 ms???
Okay ... you know that DNS requests automatically timeout and fail to the next after 2 seconds. You can assume by the 3rd or 4th level deep of DNS caches that every request to those above domains will fail at least once every 5 minutes.
Are you meaning to say that a dns request to a dns cache takes 2 seconds? It should be 2ms? And even then, is 2ms not a bit slow and is it also not depending on the size of the cache? And the speed of the medium the cache runs on? Please some more clarification here.
Hilton - yes, only trust the root. Amazing how many DNS resolvers are changing their responses these days. When does a masked NXDOMAIN start to break things? SMTP server trying to determine if a domain exists? Well they all exist when you use your ISPs cache. Sitefinder all over again.
What do you refer to as root. You mean a root cache, like in my model. Or is the root here a BIND server you run yourself, iow a real dns server?
The rest of the remark I don't understand at all. Maybe Hilton understand what you mean, but not me. And if I don't probably some other readers don't. We all have different levels of skills and knowledge. So can you please be more specific here and explain what you mean. It would make you a nice teacher!
WirelessRudy - Try 'ipconfig /displaydns' in windows. It already is caching itself. Run it a few times and check the TTL.
Well, tried that. The list stays the same, even if I did flush the cache (ipconfig /flushdns) and when I tried to type some new url's in my browser I don't see them coming up in this list neither. So am not sure what this list now exactly is. And therefore not sure what you are trying to tell me here.
Sorry, you must think I am not very smart, to start a discussion and then don't know what underlying basics might mean. But that's my way of learning. Start a discussion and during the process get new info and knowledge....
So, keep up the good work and we all benefit.