...
54.244.51.0/30 which translates to:
54.244.51.0
54.244.51.1
54.244.51.2
54.244.51.3
Ports: 5060 (UDP/TCP), 5061 (TLS)Additional links to whitelist:
https://media.twiliocdn.com/sdk/js/client/v1.9/twilio.min.js
https://media.twiliocdn.com/taskrouter/js/v1.20/taskrouter.min.js
SENDGRID WHITELIST:
sendgrid.com
sendgrid.net
sendgrid.me
sendgrid.info
...