firewall port is open, however tnsping/sqlplus hangs.
Even tried instant client, same symptoms.
Googled, check against latest installation guide , and finally found some packages is missing. In my case, they are :
compat-libcap1-1.10-1 (x86_64)
libstdc++-4.4.4-13.el6 (x86_64)
libstdc++-devel-4.4.4-13.el6.i686
this may happen when cloned by sysadmin, as packages need to be installed with both 32 and 64 bits.
