Tonight, I figured out how to add the Resolved IP Addresses for a host to measurement data and store that information for further debugging. It was very simple – I was trying to find complex solutions to this issue.
Turns out the solution is built right into PERL: The Socket module.
My thought is that I will update the table with the test config with three new columns:

  • HTTPS/HTTP
  • Hostname
  • Page information

There will likely be a new table that joins with the raw data on

  • Date
  • Agent_id
  • Test_id

And contains a comma-delimited list of all the IP addresses that the agent resolved the hostname to at the test time. This lookup will be run after the measurement, so the DNS lookup component of the measurement is not compromised.
I don’t have an ETA on this, as I want to test it fairly thoroughly before I expose the data. Adding the columns to the test config table will be transparent, but agent modification will need to be verified and then rolled out to all of the folks hosting measurement locations.
What problem does this provide a solution to?
It is vital for firms who use geographic load balancing and CDNs to verify that their data is being served from location appropriate IP addresses. I will be able to tie the information collected here into the IP-Location data I collect for other purposes and help companies ensure that this is being done.