[CentOS] change network switch need 'arp" clear cache?

we plan to change network switch and firewall machine to new one.  Network engineer told me after switch and firewall equipment change I may need run 'arp ..." to clear out cache on every CENTOS servers due to switch and firewall MAC address change.

we have 30 to 40 CENTOS 4.X and 5.X my affect.  my question are:


1. does switch and firewall equipment change need LINUX client clear cache?

2. if needed, how to clear cache and get new info about switch and firewall?