Installing php-mbstring on RHEL6

I wanted to install the mbstring PHP extension on Red Hat Enterprise Linux 6. But to my surprise, it wasn't there:

# yum install php-mbstring
Loaded plugins: rhnplugin
Setting up Install Process
No package php-mbstring available.
Error: Nothing to do

That's because the package is in the RHEL Server Optional repository.

I went into RHN and enabled the repository:

After doing yum update I could do yum install php-mbstring with no problems.



How to go to that optional repository