Hi Martin!
Yes , he will need a RALUS licence for this and it is a paid option.
You can refer to following link which will guide you through Software Compatibility List :
http://seer.support.veritas.com/docs/264484.htm
GRFS stands for "Generic Remote File System". GRFS agents include agent for MAC,UNIX and Win 9x.
Refer to http://seer.support.veritas.com/docs/191682.htm to know more about GRFS.
Thanks and regards,
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