Browser – DNS lookup

Another issue Plumbr now exposes is slowness caused by browser making a request to a DNS server to translate domain name to IP. DNS lookup Root Cause will be registered if this phase exceeded the threshold. Plumbr groups all requests to the same domain into one DNS lookup Root Cause referencing the particular domain.

Reasons why DNS lookup is slow usually are following:

  • network is bad between client and DNS server
  • DNS server is at heavy load and cannot process requests fast enough
  • DNS server is not configured properly to make fast lookups
  • short DNS TTL setting causing servers to frequently check if their cached value is up to date

To get rid of this problem one can try to improve network conditions or change DNS servers if possible.