I'm sure many people will have seen the recent security update on
gethostbyname(), etc. Apparently exim can be vulnerable to this.

This raises the question: does updating a library package actually
protect systems from the vulnerability or do daemons continue to use the
(insecure) version of the library call they linked at start up?

And indeed, if yum updates a daemon due to security fixes does the
daemon restart?

If it doesn't protect us is there practicable way to make sure we are
genuinely protected short of rebooting the whole system every time there
is a security update?

John