Tools

How to create a certificate signing request (CSR) with Subject Alternative Name (SAN) for Serv-U?

This article provides information how to create a CSR with a subject alternative name.

First published date

6/23/2023 10:43 PM

Last published date

7/11/2025 5:52 PM

Overview

Serv-U supports any kind of SSL certificate, such as Wildcard and SAN. You can generate a CSR in the Serv-U encryption tab but only for a single hostname or domain. To generate a CSR with SAN, we can use a 3rd party tool like KeyStore Explorer.

Please note that KeyStore Explorer is not a SolarWinds application but a 3rd party tool you can use to generate SAN CSR. There are other generators as well, but in this case, we will use this application.

Product section

Serv-U Managed File Transfer & Serv-U FTP Server

Resolution

  1. Download the KeyStore Explorer and install it on the Serv-U server or any machine.
  2. Launch the KeyStore Explorer, and select Create a new KeyStore.


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  1. Choose PKCS #12 and click OK.


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  1. Go to the Tools menu and then Generate Key Pair.


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  1. Leave the default RSA, click OK.


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  1. Choose version 3.
  2. In the Name box, click the icon on the right.

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  1. Enter the Common Name (The domain name Serv-U will use) and the other details, then click OK.

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  1. Click Add Extensions.

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  1. Click the + icon and then choose the Subject Alternative Name, and click OK.


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  1. Click the + icon, select the DNS name, then enter the other domain name in the General Name Value.


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  1. Do the same procedure for the other domain name. Click both OK to close the Add Certificate Extension.


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  1. Leave the default Alias, click OK, then set the password.
  2. You will see the generation successful and click OK.


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  1. Click the File menu, then click Save as.
  2. Enter the password that was set in step 13.
  3. In the filename, set your preferred name with extension .p12 (ex. san.p12) and then save.

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  1. Right-click the key store file, then select Generate CSR.


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  1. Click Browse to set the file location, then OK.

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Note: Please set a password on the Challenge field, it can be blank, but it is best practice to have one.

  1. Right-click the key store file, select Export, and select Export Key Pair.


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  1. Choose PEM, click Browse to set the file location, then click Export.


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Note: The password is for the private key; note it because it is needed when configuring in Serv-U. It can be blank, but it is best if you have one.

  1. Use the CSR when requesting the SSL certificate from the SSL certificate provider.
  2. Use the Private key in the Serv-U console when setting up the SSL certificate.

To get the Private Key from the Key Pair in step 21.

  1. Open the PEM file in Notepad.
  2. Copy the line -----BEGIN PRIVATE KEY----- up to the -----END PRIVATE KEY-----.
  3. Open a new Notepad and then paste it.
  4. Click the File menu, select Save as, and then set the filename to .key (ex. test.com.key).

To configure the SSL certificate, please see Use an existing certificate in Configure SSL for FTPS and HTTPS.