This certificate will be used by the following services: IIS, SMTP, POP, IMAP, and UM. If your server does not have a valid certificate available to encrypt communication between clients and the Client Access server or the Unified Messaging server, communication will be unencrypted, and therefore, insecure. If the certificate expires, opening Outlook will cause an annoying dialog saying: exserver.domain.local Information you exchange with this site cannot be viewed or changed by others. However, there is problem with the site's security certificate… Please find below link for more details http://technet.microsoft.com/en-us/library/bb851505%28EXCHG.80%29.aspx Girishp

Hi Sunil- A lot of the answer depends on which certificate expires and what your uses of certificates are. In typical certificate usage scenarios, users would receive pop-up warnings about the expired certificate (in Outlook or OWA). If the expiring certificate is used for secure communications with other email servers, that communication may fail. The good news is that an expired certificate can still provide encryption/protection (but with increased risk and some annoyances). Swapping out the certificate with a new one is a straight forward process. You should have a look at the following article for insight into Exchange and certificates: http://www.shudnow.net/2008/11/18/autodiscover-dns-certificates-and-what-you-need-to-know/ The above article is based on Exchange 2007. For information about certificates in Exchange 2010, see the following article: http://www.msexchange.org/articles_tutorials/exchange-server-2010/management-administration/managing-certificates-exchange-server-2010-part1.html Brian

This certificate will be used by the following services: IIS, SMTP, POP, IMAP, and UM. If your server does not have a valid certificate available to encrypt communication between clients and the Client Access server or the Unified Messaging server, communication will be unencrypted, and therefore, insecure. If the certificate expires, opening Outlook will cause an annoying dialog saying: exserver.domain.local Information you exchange with this site cannot be viewed or changed by others. However, there is problem with the site's security certificate… Please find below link for more details http://technet.microsoft.com/en-us/library/bb851505%28EXCHG.80%29.aspx Girishp

what would be the efect on my exchange infra if exchange certificate got expire