Is it possible to use SSL without a domain name?
I am using a server with Debian, Apache 2 and OpenSSL installed.
Is it possible to use SSL without a domain name for an internal network?
Yes, try "self-signed" certificates:
http://wiki.debian.org/Self-Signed_Certificate
http://www.debian-administration.org/articles/284
Is it possible to use SSL without a domain name
Yes.