startssl的免費ssl證書有一年的有效期（包括登錄startssl的用戶登錄證書和域名ssl證書）。
續期步驟爲：
1）更新用戶登錄證書
2）更新域名ssl證書
在用戶證書過期前兩星期註冊郵箱會收到類似提示郵件：
This mail is intended for the person who owns a digital certificate issued by the StartSSL Certification Authority (http://www.startssl.com/).
The Class 1, client certificate for [email protected] and serial number xxxxxx (xxxxx) is about to expire in about two weeks. Please log into the StartSSL Control Panel at https://www.startssl.com/?app=12 and get a new certificate for this purpose. Failing to update your client certificate might result in the loss of your account.
Should you have lost the client certificate which was previously issued to you, please register once again - login without the client certificate installed into your browser will not work in that case.
1、瀏覽器訪問https://www.startssl.com/?app=12，如果用戶證書已過期只能重新註冊一個帳號了。
2、點擊Validations Wizard
選擇Enter Email Address。
3、輸入email地址，點擊Continue。
4、檢查郵箱輸入驗證碼
Complete Validation
A verification code has been sent to "[email protected]".
Please check your email account now and enter the code into the text field below.
輸入驗證碼，點擊Continue。
5、郵箱驗證成功
Validation Success
You have successfully authenticated mail account "[email protected]".
You will be able to use this verification for the next 30 days, after which it expires and must be renewed.
點擊Finish。
6、點擊Certificates Wizard
選擇S/MIME and Authentication Certificate生成登陸的證書。
7、選擇要安裝的郵箱
8、安裝成功
Congratulations!
Your S/MIME client certificate is installed in your browser.
Backup this certificate to an external media. You may import this certificate to your mail client.
點擊Finish。
9、備份用戶證書
firefox：工具-選項-高級-查看證書-您的證書，下面就有需要備份的證書。
可以看到證書的有效期增加了一年（從安裝成功之日起）。
10、隨後更新域名ssl證書
過程和http://www.live-in.org/archives/1296.html第12步開始一樣。
相同的域名要等原證書過期後才能再次申請ssl證書。
在證書過期前兩星期也會收到提示郵件：
This mail is intended for the person who owns a digital certificate issued by the StartSSL Certification Authority (http://www.startssl.com/).
The Class 1, server certificate for p.live-in.org and serial number XXXXXX (XXXXX) is about to expire in about two weeks. Please log into the StartSSL Control Panel at https://www.startssl.com/?app=12 and get a new certificate for this purpose.
此時已經可以重新申請域名ssl證書了。
11、驗證完域名之後
會提示：
Ready Processing Certificate
We have gathered enough information in order to sign your certificate now.
The common name of this certificate will be set to p.live-in.org.
The certificate will have the following host names supported:
live-in.org
p.live-in.org
Please click on Continue in order to process the certificate.
點擊Continue。
12、提示等待人工審覈
Additional Check Required!
Warning You successfully finished the process for your certificate. However your certificate request has been marked for approval by our personnel. Please wait for a mail notification from us within the next 3 hours (the most). We might contact you for further questions or issue the certificate within that time. Thank you for your understanding!