AIX cifs hostname with underscore I am trying to type this comand but for some reason it takes the first and not the second version. I have entered both the host names in the host file, FYI. This command works (hostname **zq13c1** ): mkcifsmnt -f /aix_bk5 -d AIX -h zq13c1 -c 'aix_user' -p 'Cognizant123' -u 214 -g 204 -t rw This command does not work (hostname **zq13c1_bk** ): mkcifsmnt -f /aix_bk5 -d AIX -h zq13c1_bk -c 'aix_user' -p 'Cognizant123' -u 214 -g 204 -t rw

Quoting from this wiki article:

> The Internet standards (Request for Comments) for protocols mandate that component hostname labels may contain only the ASCII letters 'a' through 'z' (in a case-insensitive manner), the digits '0' through '9', and the hyphen ('-'). The original specification of hostnames in RFC 952, mandated that labels could not start with a digit or with a hyphen, and must not end with a hyphen. However, a subsequent specification (RFC 1123) permitted hostname labels to start with digits. No other symbols, punctuation characters, or white space are permitted.

The underscore `_` is not a valid character in a hostname.