Understanding NAT DHCP

Understanding NAT DHCP

What is DHCP?

DHCP (Dynamic Host Configuration Protocol) automatically assigns unique network names (IP addresses) to devices on a network. Without DHCP, every device would need to be manually configured.

The NAT DHCP Menu on an SM

DHCP Client Statistics

This is the DHCP the SM itself pulls from our infrastructure. You should see an Assigned IP, Subnet Mask, and Default Gateway.

DHCP Server Statistics

This is the DHCP that the customer's device (usually a router) is pulling from the SM. The lease stays active for 30 days and refreshes if the device is still connected.

You can see all devices the customer has connected to the SM — different routers, computers (if they bypassed), etc.

If you see more than one device: Ask the customer what it is. If they claim to have only one device plugged in:

• Their router is either dying (some routers change MAC address as they fail)
• Or it's set to bridge mode (if they don't know what bridge mode is, the router is dying)

What is a NAT?

NAT (Network Address Table) holds information about all connections made through the equipment.

• Original IP — The device sending the request (usually just the customer's router)
• Final IP — The customer's public IP address
• Port — Different traffic types use different ports (e.g., ports 80 and 443 for normal web traffic)

The NAT table holds 2,048 entries by default. If the customer exceeds this, they can't connect to new websites until entries time out and clear.

To check if this has happened: Statistics → NAT Stats → check Out Of Resources count.