Teams // External Access - Federation

[ErikVet]

Hello Teams Community,

just a quick question.

Tenant A and Tenant B have configured a whitelist regarding Federation  // External Access from Tenant A to Tenant B. 

Tenant A uses different Subdomains in it's organisation. 

PrefixA.contoso.com

PrefixB.contoso.com 

Does Tenant B has to whitelist just the domain contoso.com or all subdomains which Tenant A is using. 

Or say it with other words, does External Access // Federation work on Domains or also subdomains. 

Many Greetings
Erik

[#2 · Accepted solution]

@ErikVet You would need to allow all the subdomains, it's not a wildcard for all subs.

[#3]

If and Org has more than one subdomain, does this mean that each domain will treat the other ones users as externals?