It’s not uncommon to need load testing on systems that are not openly connected to the Internet, or that have sophisticated filtering in place to block potential denial-of-service attacks or other automated access.

Configuration settings for tools like security groups, firewalls, and DDoS mitigation can typically be configured to allow connections from specific IP addresses to circumvent the filtering.

Loader’s cluster of load generators is hosted on public cloud instances, and have dynamically assigned IP addresses. Loader’s API provides an endpoint that customers can use to get a list of the current IP addresses:

export APIKEY=...
curl https://api.loader.io/v2/servers \
	--header "loaderio-auth: $APIKEY"

The output will look something like this:

{
  "ip_addresses": [
    "107.21.10.110",
    "18.204.4.113",
    "18.212.104.123",
    "3.227.240.24",
    "3.227.251.73",
    "3.230.143.8",
    "3.235.15.10",
    "3.235.49.7",
    "3.89.116.106",
    "44.192.21.154",
    "44.197.182.180",
    "54.198.48.58",
    "54.224.168.229",
    "54.86.144.132",
    "54.89.190.46",
    "54.91.193.0"
  ]
}

Add these IP addresses to the firewall, security group, or the configuration for any other filtering systems in place to allow Loader to connect to the target.