My company have server to host application for internal use only. So this server is on internet but IP are restricted only from office.
Is it possible to use Let’s Encrypt to have Https ? I ask that because in the FAQ we can’t know the IP of let’s encrypt so how the validation will be done ?
Has this server got a fully qualified domain name ?
If it is on the internet, but restricted to your office IP, then the easiest is to allow full access to domain/.well-known/acme-challenge for any IP address, but of course restrict other folders to your office IP.
Alternatively, you could perform a DNS challenge rather than a http challenge.