When setting up a new monitor, you must whitelist NS1 monitoring nodes on the machines upon which health checks are performed. You can always find the current set of monitoring endpoint addresses and regions using the following API command.
curl -X GET -H "X-NSONE-Key: $API_KEY" https://api.nsone.net/v1/monitoring/regions | jq .
This produces a human-readable JSON response with the name, code, and IP(v4/v6) information for each region. For example:
[ { "name": "Dallas", "code": "dal", "subnets": [ "192.0.2.40/29", "2001:db8:4009:3::/64" ] }, { "name": "Singapore", "code": "sin", "subnets": [ "198.51.100.224/29", "2001:db8:1000:3::/64" ] }, { "name": "San Jose", "code": "sjc", "subnets": [ "192.0.2.152/29", "2001:db8:400c:3::/64" ] }, { "name": "New York", "code": "lga", "subnets": [ "203.0.113.16/29", "2001:db8:4004:3::/64" ] }, { "name": "Amsterdam", "code": "ams", "subnets": [ "203.0.113.48/29", "2001:db8:e:3::/64" ] } ]
Notice that the response uses the following format:
{ "subnets": [ LIST_OF_SUBNETS ], "code": "CITY_CODE", "name": "CITY_NAME" }
For further assistance, please contact the NS1 support team.