Hi Eric,
I think the hostname has included the special character as "_" that works to nslookup but failed to ping command.
See the documented in the resolv.conf man page:
====
options allow_special all | { \char }
Option for defining valid characters in hostnames. Specify all to disable
hostname checking (allow all characters) or define a set of valid charac-
ters by using the { \char } syntax, where char is the character you want to
allow. For example, you can allow the semicolon, underscore, and colon
characters by using { \; \_ \: }.
Disabling hostname checking altogether is not recommended. By default, the
allow_special option is not set and strict hostname checking is enforced.
====
If the special character "_" is used in DNS DB. The solution will be added the following definition into resolv.conf
Such as:
options allow_special { \_ }
Good luck,
Richard.
