It really depends on how often your ISP cleans their DNS records, generally...

It really depends on how often your ISP cleans their DNS records, generally when a new DNS server is setup the initial inquiries take a while unless you are making your new calls from another DNS server such as your ISP of google's public DNS servers.

I have experienced noticeable lookup speed increase moving from verizon's DNS servers to google's DNS servers at 8.8.4.4 and 8.8.8.8

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