With the hosting pack v2 for Lync 2013 Microsoft made the Skype federation available for hosting environments. To configure the federation, follow the official Microsoft guide.
If you have configured Skype federation, you have to enable Federation on to tenant:
Import-Module LyncOnline
Set-CsTenantFederationConfiguration -Tenant [TenantID] -AllowFederatedUsers $true
Set-CsTenantFederationConfiguration -Tenant [TenantID] -AllowPublicUsers $true
If you try to send some IM’s to a Skype user, you get the following error message in the OCS logger
ms-diagnostics: 27000;reason="To-Uri Domain is not in the sender-tenant allow list";
To get the federation working, you have to add the following domains to the tenant allow list. This is the way Microsoft do this on Office 365.
$d1 = New-CsEdgeDomainPattern -Domain "br.live.com"
$d2 = New-CsEdgeDomainPattern -Domain "hotmail.ch"
$d3 = New-CsEdgeDomainPattern -Domain "hotmail.co.il"
$d4 = New-CsEdgeDomainPattern -Domain "hotmail.co.jp"
$d5 = New-CsEdgeDomainPattern -Domain "hotmail.co.th"
$d6 = New-CsEdgeDomainPattern -Domain "hotmail.co.uk"
$d7 = New-CsEdgeDomainPattern -Domain "hotmail.com"
$d8 = New-CsEdgeDomainPattern -Domain "hotmail.com.ar"
$d9 = New-CsEdgeDomainPattern -Domain "hotmail.com.tr"
$d10 = New-CsEdgeDomainPattern -Domain "hotmail.es"
$d11 = New-CsEdgeDomainPattern -Domain "hotmail.de"
$d12 = New-CsEdgeDomainPattern -Domain "hotmail.fr"
$d13 = New-CsEdgeDomainPattern -Domain "hotmail.it"
$d14 = New-CsEdgeDomainPattern -Domain "live.at"
$d15 = New-CsEdgeDomainPattern -Domain "live.be"
$d16 = New-CsEdgeDomainPattern -Domain "live.ca"
$d17 = New-CsEdgeDomainPattern -Domain "live.cl"
$d18 = New-CsEdgeDomainPattern -Domain "live.cn"
$d19 = New-CsEdgeDomainPattern -Domain "live.co.in"
$d20 = New-CsEdgeDomainPattern -Domain "live.co.kr"
$d21 = New-CsEdgeDomainPattern -Domain "live.co.uk"
$d22 = New-CsEdgeDomainPattern -Domain "live.co.za"
$d23 = New-CsEdgeDomainPattern -Domain "live.com"
$d24 = New-CsEdgeDomainPattern -Domain "live.com.ar"
$d25 = New-CsEdgeDomainPattern -Domain "live.com.au"
$d26 = New-CsEdgeDomainPattern -Domain "live.com.co"
$d27 = New-CsEdgeDomainPattern -Domain "live.com.mx"
$d28 = New-CsEdgeDomainPattern -Domain "live.com.my"
$d29 = New-CsEdgeDomainPattern -Domain "live.com.pe"
$d30 = New-CsEdgeDomainPattern -Domain "live.com.ph"
$d31 = New-CsEdgeDomainPattern -Domain "live.com.pk"
$d32 = New-CsEdgeDomainPattern -Domain "live.com.pt"
$d33 = New-CsEdgeDomainPattern -Domain "live.com.sg"
$d34 = New-CsEdgeDomainPattern -Domain "live.com.ve"
$d35 = New-CsEdgeDomainPattern -Domain "live.de"
$d36 = New-CsEdgeDomainPattern -Domain "live.dk"
$d37 = New-CsEdgeDomainPattern -Domain "live.fr"
$d38 = New-CsEdgeDomainPattern -Domain "live.hk"
$d39 = New-CsEdgeDomainPattern -Domain "live.ie"
$d40 = New-CsEdgeDomainPattern -Domain "live.in"
$d41 = New-CsEdgeDomainPattern -Domain "live.it"
$d42 = New-CsEdgeDomainPattern -Domain "live.jp"
$d43 = New-CsEdgeDomainPattern -Domain "live.nl"
$d44 = New-CsEdgeDomainPattern -Domain "live.no"
$d45 = New-CsEdgeDomainPattern -Domain "live.ph"
$d46 = New-CsEdgeDomainPattern -Domain "live.ru"
$d47 = New-CsEdgeDomainPattern -Domain "live.se"
$d48 = New-CsEdgeDomainPattern -Domain "livemail.com.br"
$d49 = New-CsEdgeDomainPattern -Domain "livemail.tw"
$d50 = New-CsEdgeDomainPattern -Domain "messengeruser.com"
$d51 = New-CsEdgeDomainPattern -Domain "msn.com"
$d52 = New-CsEdgeDomainPattern -Domain "passport.com"
$d53 = New-CsEdgeDomainPattern -Domain "sympatico.ca"
$d54 = New-CsEdgeDomainPattern -Domain "tw.live.com"
$d55 = New-CsEdgeDomainPattern -Domain "webtv.net"
$d56 = New-CsEdgeDomainPattern -Domain "windowslive.com"
$d57 = New-CsEdgeDomainPattern -Domain "windowslive.es"
$d58 = New-CsEdgeDomainPattern -Domain "outlook.com"
Greetings
nd