Is there a Allow list of IP's for the I/O webhooks that make external calls?

[user05162]

I am using I/O events to make external calls. It is failing as the the destination server only allows requests from Specific IP's. Looking for a list of IP's that Adobe uses for making webhook calls.

[navink386520]

There are no list of specific IP,  the only condition is the IP has to be exposed to internet, either use ngrok or host it in Heroku