Exchange Delegation Federation / Microsoft Federation Gateway / Renew Certificate

EAC is alerting for certificate expiration.

It is easier to renew the certificate before expiration.

Generate new self signed certificate from exchange shell

Key Identifier ( Random name for the key)

$:\> $SKI = [System.Guid]::NewGuid().ToString("N");
$:\> echo $SKI
  3ecaf8d9942c4fb4848e6201810e0734

Create Key

New-ExchangeCertificate -DomainName 'Federation' -FriendlyName "Exchange Delegation Federation" `
  -Services Federation -SubjectKeyIdentifier $SKI -PrivateKeyExportable $true

Thumbprint                                Subject                                                                                                                                                                
----------                                -------                                                                                                                                                                
133F83817AD86C127C0A71B92214C52D6B3A4D31  CN=Federation                                                                                                                                                          

Set the "next" in exchange

$:\>Set-FederationTrust -Identity "Microsoft Federation Gateway" -Thumbprint 133F83817AD86C127C0A71B92214C52D6B3A4D31 -RefreshMetaData

WARNING: The federation trust has changed to prepare for the usage of a new certificate for Federation. `
You should update all TXT proof-of-ownership  records that were previously set in DNS for all the domains `
configured for Federation before publishing the new certificate.
The new hash-value should be replaced with the OrgNextCertificate proof value output generated with `
"Get-FederatedDomainProof -DomainName example.com".

Update DNS TXT record

Find the TXT record responsible for Federation

$:\>nslookup -type=txt example.com  8.8.8.8

example.com	text = "v=spf1 mx -all"
example.com	text = "google-site-verification=...
example.com	text = ""

Authoritative answers can be found from:

izqi33FMhbo05dK8M+Tek1gj7frqmnatO1hM5MWLx98yLivsrIJQ6M1ZkSqGwma0Fjv4W90bmSE4...