Upstream servers...

rjbarlow

Hello techies,

studying DNS, some time I encountered these "upstream servers" in some question (often they was the wrong answer), but I don't know in fact what they mean for.

Someone can clarify this to me please?

Thank You.

rj

dynamik

Basically, those are just DNS servers which provide information to a client or another DNS server.

ISP
|
1
/ | \
2 3 4

So for 2, 3, and 4, 1 and ISP would be upstream of them. ISP would be upstream of 1. Conversely, 2, 3, 4 would be downstream of 1 and ISP. It depends on your hierarchy and forwarding options.