cert: additional ip addresses in SANs

[tristan-weil]

Feature Description

The command consul tls cert create -additional-dnsname=<value> allows generating certs with additional names (+ localhost and 127.0.0.1) in the Subject Alternative Names, which is really useful and easy to use.

I would like to have a similar feature to add IP addresses in the SANs.

Use Case(s)

My personal use-case: I'm testing Consul and Vault on the same machine with multiple daemons bound on local addresses (127.0.1.1, 127.0.2.1, 127.0.3.1, 127.0.4.1, etc.). And it works really well but the addresses need to be declared in /etc/hosts with corresponding hostnames. I have, of course, errors if I request directly the daemons on their IP with curl or other external tools.

More real use-cases:

• no access to the DNS servers for the requesting hosts
• different vlans and external tools using IP addresses (like monitoring)