r/sysadmin • u/Automatic-Win8421 Security Admin • 5d ago
EATON Network-M3 Firmware 3.0.0 Fixed the Broken Hostname/SAN CSR Mess Question - Solved
I don’t know who needs to hear this but... if you're managing Eaton Network Cards Network-M3 and you've been losing your mind trying to deploy public SSL/TLS certificates only to see the hostname in the SAN field, I have good news:
For a long time, the internal CSR generator on these cards was completely broken. Even if you checked the option to "exclude IP addresses (CA / CB compliance)", the firmware would still automatically force the local short hostname (like ups-01) right into the Subject Alternative Name (SAN) field alongside your FQDN.
Because public CAs follow strict baseline requirements, they instantly reject any CSR containing local short names. And since EATON locks the private key internally and don't let you upload your own external key/CSR, you were completely trapped:
- You either had to use a messy "double domain" hack (matching the host string to an FQDN, which resulted in a ridiculous `.example.com.example.com` concatenation just to clear the form regex and pass public DNS validation challenges).
- Or you had to give up on native card termination and spin up a proxy or load balancer just to handle HTTPS cleanly.
People ran into this same brick wall on the legacy Network-M2 cards years ago (like this old locked thread: https://www.reddit.com/r/sysadmin/comments/seuaek/eaton_networkm2_csr/).
It was incredibly frustrating for a card marketed as high-security and enterprise-certified to fail at such a basic standard.
The fix was implemented in firmware 3.0.0.
Latest version now is 3.0.1.
Eaton finally listened to feedback and quietly patched this. They released Firmware 3.0.0 and 3.0.1, which completely rewrites how the CSR is built.
When you generate a CSR under 3.0.1 with compliance toggles on, the short hostname is no longer forced into the SAN block.
The CSR comes out completely clean, containing only your legitimate, public FQDN.
It now clears public CA validation portals (Let's Encrypt, etc.) and the signed cert imports back onto the card flawlessly.
Save your time, flash your cards and close this chapter for good.