今天晚上突然發現公司的zimbra郵件服務器頁面無法打開，進入系統查看下zimbra啓動的服務項，發現ldap啓動失敗，於是網上找了下資料，現在分享一下心得（複製過來的）。實測，有效！
ZCS默認的證書只能使用一年，到期後需要重新簽發，如果不簽發，可以會使ZCS的服務無法啓動，表現的情況爲：
Starting ldap...Done.
Unable to determine enabled services from ldap.
Enabled services read from cache. Service list may be inaccurate.
ldap Stopped
logger Stopped
分爲兩種情況：
一 ZCS服務正常，但想延長證書使用的時間；
用root執行裏下命令，簽發一個可以使用20年的證書。
#/opt/zimbra/bin/zmcertmgr createca -new
#/opt/zimbra/bin/zmcertmgr deployca
#/opt/zimbra/bin/zmcertmgr createcrt -new -days 7300
#/opt/zimbra/bin/zmcertmgr deploycrt self
#/opt/zimbra/bin/zmcertmgr viewdeployedcrt
二 如果ZCS服務已經無法全部啓動，那麼先停止ZCS服務，執行以上命令後，再啓動ZCS服務即可。
經測試，簽發20年的證書全部成功，簽發50年的證書可能會失敗。
下面爲簽發的過程（此過程中有部分failed，僅供參考，實際成功簽發時代碼不同）：
[root@mail ~]# /opt/zimbra/bin/zmcertmgr createca -new
** Creating /opt/zimbra/ssl/zimbra/ca/zmssl.cnf...done
** Creating CA private key /opt/zimbra/ssl/zimbra/ca/ca.key...done.
** Creating CA cert /opt/zimbra/ssl/zimbra/ca/ca.pem...done.
[root@mail ~]# /opt/zimbra/bin/zmcertmgr deployca
** Importing CA /opt/zimbra/ssl/zimbra/ca/ca.pem into CACERTS...done.
** Saving global config key zimbraCertAuthorityCertSelfSigned...failed.
** Saving global config key zimbraCertAuthorityKeySelfSigned...failed.
** Copying CA to /opt/zimbra/conf/ca...done.
[root@mail ~]# /opt/zimbra/bin/zmcertmgr createcrt -new -days 7300
Validation days: 7300
** Creating /opt/zimbra/conf/zmssl.cnf...done
** Backup /opt/zimbra/ssl/zimbra to /opt/zimbra/ssl/zimbra.20110415115810
** Generating a server csr for download self -new -keysize 1024
** Creating /opt/zimbra/conf/zmssl.cnf...done
** Backup /opt/zimbra/ssl/zimbra to /opt/zimbra/ssl/zimbra.20110415115810
** Retrieving Commercial CA cert from ldap...failed.
** Creating server cert request /opt/zimbra/ssl/zimbra/server/server.csr...done.
** Saving server config key zimbraSSLPrivateKey...failed.
** Signing cert request /opt/zimbra/ssl/zimbra/server/server.csr...done.
[root@mail ~]# /opt/zimbra/bin/zmcertmgr deploycrt self
** Saving server config key zimbraSSLCertificate...failed.
** Saving server config key zimbraSSLPrivateKey...failed.
** Installing mta certificate and key...done.
** Installing slapd certificate and key...done.
** Installing proxy certificate and key...done.
** Creating pkcs12 file /opt/zimbra/ssl/zimbra/jetty.pkcs12...done.
** Creating keystore file /opt/zimbra/mailboxd/etc/keystore...done.
** Installing CA to /opt/zimbra/conf/ca...done.
[root@mail ~]# /opt/zimbra/bin/zmcertmgr viewdeployedcrt
::service mta::
notBefore=Apr 15 03:58:20 2011 GMT
notAfter=Dec 31 03:58:20 2030 GMT
subject= /C=US/ST=N/A/O=Zimbra Collaboration Suite/OU=Zimbra Collaboration Suite/CN=mail.test.com.cn
issuer= /C=US/ST=N/A/L=N/A/O=Zimbra Collaboration Suite/OU=Zimbra Collaboration Suite/CN=mail.test.com.cn
SubjectAltName=
::service proxy::
notBefore=Apr 15 03:58:20 2011 GMT
notAfter=Dec 31 03:58:20 2030 GMT
subject= /C=US/ST=N/A/O=Zimbra Collaboration Suite/OU=Zimbra Collaboration Suite/CN=mail.test.com.cn
issuer= /C=US/ST=N/A/L=N/A/O=Zimbra Collaboration Suite/OU=Zimbra Collaboration Suite/CN=mail.test.com.cn
SubjectAltName=
::service mailboxd::
notBefore=Apr 15 03:58:20 2011 GMT
notAfter=Dec 31 03:58:20 2030 GMT
subject= /C=US/ST=N/A/O=Zimbra Collaboration Suite/OU=Zimbra Collaboration Suite/CN=mail.test.com.cn
issuer= /C=US/ST=N/A/L=N/A/O=Zimbra Collaboration Suite/OU=Zimbra Collaboration Suite/CN=mail.test.com.cn
SubjectAltName=
::service ldap::
成功，哈哈。