Renew Exchange Certificate Self Sign

Exchange Server 2007: Renewing the self-signed certificate

Exchange Server 2007 issues itself a self-signed certificate for use with services like SMTP, IMAP, POP, IIS and UM. The certificate is issued for a period of one year.

The self-signed certificate meets an important need – securing communication paths for Exchange services by default. Nevertheless, one should treat these certificates as temporary. Although the self-signed certificates work perfectly well for internal SMTP communication between Hub Transport servers, and between Hub Transport and Edge Transport servers, it’s not recommended to use them for any client communication on an ongoing basis. For most deployments, you will end up procuring a certificate from a trusted 3rd-party CA (or perhaps an internal CA in organizations with PKI deployed).

Should you decide to leave the self-signed certificate(s) on some servers and continue to use them, these will need to be renewed when they expire — just as you would renew certificates from 3rd-party or in-house CAs.

1 To renew the certificate for server e12postcard.e12labs.com, a server with CAS and HTroles installed:

Get-ExchangeCertificate -domain “e12postcard.e12labs.com” | fl

Note the services the certificate is enabled for (by default: POP, IMAP, IIS, SMTP on CAS + HT servers). Copy the thumbprint of the certificate.

Get a new certificate with a new expiration date:

Get-ExchangeCertificate -thumbprint “C5DD5B60949267AD624618D8492C4C5281FDD10F” | New-ExchangeCertificate

To create a new certificate with an exportable private key, use the PrivateKeyExportable parameter. For example:
New-ExchangeCertificate -PrivateKeyExportable $true

If the existing certificate is being used as the default SMTP certificate, you will get the following prompt. The default SMTP certificate is used to encrypt SMTP sessions between transport servers in your organization.