Forum Discussion
CirrostratusTesting GTM topology results
NimbostratusNot sure what your requirements are, but Pingdom.com has geographically distributed monitoring sites (list of source IP address is available from Pingdom). If you set up Pingdom to monitor a URL, you will see each monitoring request come from the respective geo location.
NimbostratusVery helpful website - the DNS propogation website. If you are having trouble in one area or region, like you stated, you can use any online load testing site to test specific regions. Load Impact is one like the other person provided. I use LoadView since I can do some testing for free and I can choose the locations I wish to test in. For example, I want to test in Australia, scale up to 10 or 1,000 users at once and record it so I can play it back and see what is actually going on, then run that script every minute for the next week and only send me the high level concerns. Not sure if that would be helpful or not, but you can check them out here: https://www.loadview-testing.com/