There are many posts out there showing the process to modify the /etc/fstab file to include mounting a CIFS share to a Windows based system. The base Ubuntu Wiki does a great job, however this post is a quick tip for the .smbcredentials file to pass along the domain name to my Openfiler shares.
The Ubuntu credentials section does reference a domain, however I ended up having issues when connecting to my Openfiler system using the username@domain syntax. The Openfiler system itself contains shares that use Active Directory group based authentication from a Domain Controller. Adding the “domain” line to the .smbcredentials file worked for the specific situation. Below is the example file. Note that the @domain syntax is not required with the additional domain parameter.
username=notreal password=notrealpw domain=domain.local