Customer Premises Equipment

Reboot

In the first instance reboot all equipment used to deliver the internet to the customers site including the routers, switches and Network Termination equipment. This is usually as simple as powering it down for 30 seconds the switching on again if in doubt check user guides or consult the manufacturer.

Cables

Check that the cables between the customers equipment and the services termination equipment are inserted correctly and working. Try alternative or new cables to ensure that this is not where the problem is.

Routers

Ensure that the configuration of the routers has been checked to ensure that is is still in place. Don't assume that nothing has changed. A power outage or firmware upgrade could have cleared the configuration. A member of staff could have made changes to the config unbeknownst to the customer.

Check the router manufacturers website or user guide to see what the LEDs indicate and conduct further investigations based on their guidance.

Firewalls

If there is firewall in the path to delivering the connectivity this should be checked by the relevant maintaining party the vendor.