WAGO 852-1305 Manual page 97

WAGO-ETHERNET-Zubehör 852
852-1305 8/4-Port 100BASE-T/1000BASE-SX/LX
"Untrusted Ports" are connected to subscribers. The switch discards DHCP
packets from untrusted ports in the following situations:
• The packet is a DHCP server packet (e.g., "OFFER", "ACK" or "NACK").
• The source MAC address and source IP address in a packet do not match
any of the current bindings.
• The source MAC address and source port in a "RELEASE" or "DECLINE"
packet do not match any of the current bindings.
• The transmission rate of the DHCP packets received are too high.
DHCP Snooping Database
The switch stores the binding table in volatile memory. If the switch restarts, it
loads the static bindings from non-volatile memory, but loses the dynamic
bindings, so that the devices in the network have to send DHCP requests again.
Configuring DHCP Snooping
Follow the steps below to configure "DHCP Snooping" on the switch:
1. Enable "DHCP Snooping" on the switch.
2. Enable "DHCP Snooping" for each VLAN.
3. Configure "Trusted Ports" and "Untrusted Ports".
4. Configure the static bindings.
DHCP Snooping
The switch drops all DHCP requests if "DHCP Snooping" is enabled, but there
are no "Trusted Ports".
If the port link fails, the entries from this port are deleted from the "DHCP
Snooping" binding table.
You must first enable global "DHCP Snooping" and "DHCP Snooping" for
VLANs.
Manual
1.1.0
Enhanced Features 97