Whitelisting Fabric & Crashlytics IP

Mike from Fabric and Firebase here. We don't support IP whitelisting as our IP addresses can and do change quite frequently. You should whitelist the following domains:

*.crashlytics.com
*.fabric.io

Update as of July 2020:

From the recent contact with the Firebase team, we got the following details:

You can whitelist the following domains on ports 80 and 443:

For Firebase Crashlytics (SDK versions 4.x and up):

*.crashlytics.com
crashlyticsreports-pa.googleapis.com

For Fabric Crashlytics (SDK versions 3.x):

*.crashlytics.com
*.fabric.io

For Firebase Crashlytics, there's one more domain which needs to be whitelisted even though it's not officially informed by Firebase team

firebasecrashlyticssymbols.googleapis.com