Slack webhook - Which IPs should I open?

Question

We want to use Slack Webhook (Outgoing Webhook) with an internal web service.

Our company is behind a firewall, so outside connections must be whitelisted.

It appears that Slack has multiple addresses it will send the API request from, and they don't seem to be documented.

Which IPs/Ports should we open in the firewall (whitelist) in order to allow slack's outgoing webhooks to connect to our internal web service?

Answer 1

I know this is an old question, but I was looking for something like this myself. I think the one answer thats there doesnt really understand the question as such.

ngrok could sort-of solve an issue here, but its not quite what was asked.

Mapping ports from external to internal on a firewall that would be at a company is trivial. What I think the originator was asking was "what IP addresses do slack use when calling our service" so that you can firewall the service off to only allow access from those IP's (hence the whole white listing thing).

Simple answer as far as i can see is they are basically using lambda and various sources within AWS which makes that rather hard