My IPSec tunnel (or VPN) to a site is down. How do I get it back?

Raise a ticket with the site name and, where relevant, the third party involved (for example a data provider or O&M system). Note the date and time the tunnel went down. VPN and IPSec faults are a recognised support category, and we will check the Centrii side of the tunnel and coordinate any change needed on the remote side.