Secure connections (SSL/TLS) : How to offload HTTPS : Generating a certificate signing request
Generating a certificate signing request
Many commercial certificate authorities (CAs) will provide a web site where you can generate your own certificate signing request (CSR). A CSR is an unsigned certificate file that the CA will sign. When the CSR is generated, the associated private key that the appliance will use to sign and/or encrypt connections with clients is also generated.
If your CA does not provide this, or if you have your own private CA such as a Linux server with OpenSSL, you can use the appliance generate a CSR and private key. This CSR can then be submitted for verification and signing by the CA.
To generate a certificate request
1. Go to System > Certificates > Local.
To access this part of the web UI, your administrator's account access profile must have Read-Write permission to items in the System category. For details, see “Permissions”.
2. Click Generate.
A dialog appears.
3. Configure the certificate signing request:
Setting name
Certification Name
Type a unique name for the certificate request file, such as www_example_com, that can be referenced in other parts of the configuration. Do not use spaces or special characters. The maximum length is 35 characters.
Note: This is the name of the CSR file, not the host name/IP contained in the certificate’s Subject: line.
Subject Information
Includes information that the certificate is required to contain in order to uniquely identify the FortiADC appliance. This area varies depending on the ID Type selection.
ID Type
Select the type of identifier to use in the certificate to identify the FortiADC appliance:
Domain NameType the FQDN of the FortiADC appliance, such as, in the Domain Name field. This does not require that the IP address be static, and may be useful if, for example, your network has a dynamic public IP address and therefore clients connect to it via dynamic DNS. Do not include the protocol specification (http://) or any port number or path names.
Host IP — Type the static public IP address of the FortiADC appliance in the IP field. If the FortiADC appliance does not have a static public IP address, use E-Mail or Domain Name instead.
Note: If your network has a dynamic public IP address, you should not use this option. An Unable to verify certificate or similar error message will be displayed by users’ browsers when your public IP address changes. Instead,
E-Mail — Type the email address of the owner of the FortiADC appliance in the E-mail field. Use this if the appliance does not require either a static IP address or a domain name.
The type you should select varies by whether or not your FortiADC appliance has a static IP address, a fully-qualified domain name (FQDN), and by the primary intended use of the certificate.
For example, if your FortiADC appliance has both a static IP address and a domain name, but you prefer to make HTTPS connections to the web UI by the domain name, you might prefer to generate a certificate based upon the domain name of the FortiADC appliance, rather than its IP address.
Depending on your choice for ID Type, related options appear.
Type the static IP address of the FortiADC appliance, such as
The IP address should be the one that is visible to clients. Usually, this should be its public IP address on the Internet, or a virtual IP that you use NAT to map to the appliance’s IP address on your private network.
This option appears only if ID Type is Host IP.
Domain Name
Type the fully qualified domain name (FQDN) of the FortiADC appliance, such as
The domain name must resolve to the IP address of the FortiADC appliance or back-end server according to the DNS server used by clients. (If it does not, the clients’ browsers will display a Host name mismatch or similar error message.) For more information, see “Configuring the physical network interfaces”.
This option appears only if ID Type is Domain Name.
Type the email address of the owner of the FortiADC appliance, such as
This option appears only if ID Type is E-Mail.
Optional Information
Includes information that you may include in the certificate, but which is not required.
Organization Unit
Type the name of your organizational unit (OU), such as the name of your department. This is optional.
To enter more than one OU name, click the + icon, and enter each OU separately in each field.
Type the legal name of your organization. This is optional.
Locality (City)
Type the name of the city or town where the FortiADC appliance is located. This is optional.
Type the name of the state or province where the FortiADC appliance is located. This is optional.
Select the name of the country where the FortiADC appliance is located. This is optional.
Type an email address that may be used for contact purposes, such as This is optional.
Key Type
Displays the type of algorithm used to generate the key.
This option cannot be changed, but appears in order to indicate that only RSA is currently supported.
Key Size
Select a secure key size of 512 Bit, 1024 Bit, 1536 Bit or 2048 Bit. Larger keys are slower to generate, and make FortiADC slower to decrypt/encrypt each packet that uses the key, but provide better security.
Enrollment Method
Select either:
File Based — You must manually download and submit the resulting certificate request file to a certificate authority (CA) for signing. Once signed, upload the local certificate.
Online SCEP — The FortiADC appliance will automatically use HTTP to submit the request to the simple certificate enrollment protocol (SCEP) server of a CA, which will validate and sign the certificate. For this selection, two options appear. Enter the CA Server URL and the Challenge Password.
4. Click Save.
The FortiADC appliance creates a private and public key pair. The generated request includes the public key of the FortiADC appliance and information such as the FortiADC appliance’s IP address, domain name, or email address. The FortiADC appliance’s private key remains confidential on the FortiADC appliance. The Status column of the new CSR entry is Pending.
5. Select the row that corresponds to the certificate request.
6. Click Download.
Standard dialogs appear with buttons to save the file at a location you select. Your web browser downloads the certificate request (.csr) file. Time required varies by the size of the file and the speed of your network connection.
7. Upload the certificate request to your CA.
After you submit the request to a CA, the CA will verify the information in the certificate, give it a serial number, an expiration date, and sign it with the public key of the CA.
8. If you are not using a commercial CA whose root certificate is already installed by default on web browsers, download your CA’s root certificate, then install it on all computers that will be connecting to your appliance. (If you do not install these, those computers may not trust your new certificate.)
9. When you receive the signed certificate from the CA, upload the certificate to the FortiADC appliance (see “Uploading a server certificate”).
See also
Uploading a server certificate