Help with Certs. Dropping on VPN Edge Boxes

Archived from groups: comp.security.firewalls (More info?)

Our organization is implementing branch office VPN connections to a
number of sites using SofaWare VPN Edge boxes and CheckPoint FW1/VPN-1
on the receiving end. A number of sites have broadband service with
dynamic WAN IP addresses. One of our vendor's engineers has set up
certificate authentication as he says its the only option with a
dynamic IP. The problem is, the certificates are dropping frequently
and must be re-installed. This initially seemed to happen if there
was a momentary power fluctuation. UPS units have been put in place
where they weren't before, but the cert problem continues. When the
cert drops, Internet access is still active but the VPN tunnel to our
main site is out until re-installation. Any help on whether we are
locked into using certificates, and what might fix the issue if we
are? Thank you.