Configuring a custom HTTPS certificate on a Netgear Switch (e.g. GS724T)

First, this should work on any Netgear firmware with a similar UI, but for reference, this is a GS724Tv4 with firmware 6.3.0.9.

I’m going to assume existing knowledge of how to create a root CA, intermediate CA, and create and sign certificates (if not, see e.g. OpenSSL Certificate Authority). We’ll need the following:

• Root CA certificate (root.cert.pem)
• Intermediate CA certificate (intermediate.cert.pem)
• Server certificate with commonname for the switch (switch.cert.pem)
• Server key corresponding to the server certificate (switch.key.pem)
• DH 1024-bit params, perhaps 2048-bit would be better (dhparams.pem)

Create two files:

• The cert chain: cat root.cert.pem intermediate.cert.pem > ca-chain.pem
• The certificate + key: cat switch.cert.pem switch.key.pem > switch-combined.pem

In the switch’s web UI:

1. Security → Access → HTTPS → HTTPS Configuration → Set “HTTPS Admin Mode” to “Disable”, Apply.
2. Security → Access → HTTPS → Certificate Management → Set “Delete Certificates”, Apply.
3. Maintenance → Download → HTTP File Download
   1. Select “SSL DH Strong Encryption Parameter PEM File”, and choose dhparams.pem, Apply.
   2. Select “SSL Trusted Root Certificate PEM File”, and choose ca-chain.pem, Apply.
   3. Select “SSL Server Certificate PEM File”, and choose switch-combined.pem, Apply.
4. Security → Access → HTTPS → Certificate Management → Verify indicates “Certificate Present: Yes”.
5. Security → Access → HTTPS → HTTPS Configuration → Set “HTTPS Admin Mode” to “Enable”, Apply.

Now you should have working HTTPS with your CA-signed cert.

Do not try to use a 2048 bit DH Strong encryption parameter as it prevented HTTPS Admin Mode from working. The certificate management tab would show that a certificate was present.

However, the GUI interface would give errors about being unable to find some missing functions when attempting to enable HTTPS Admin Mode and while the GUI would show that it was enabled, nothing would listen on the assigned port.

Disabling the HTTPS Admin Mode, deleting the certificates and following the certificate loading sequence above with a 1024-bit DH strong encryption parameter got it to work.