Siemens S223, S323 user manual Dhcp Rate Limit, Dhcp Lease Limit, Source MAC Address Verification

User Manual	UMN:CLI
SURPASS hiD 6615 S223/S323 R1.5

8.8.7.3DHCP Rate Limit

To set the number of DHCP packet per second (pps) that an interface can receive, use the following command.

Command		Mode	Description
ip dhcp snooping	limit-rate		Sets a rate limit for DHCP packets. (unit: pps)
PORTS <1-255>
		Global
no ip dhcp snooping limit-rate			Deletes a rate limit for DHCP packets.
PORTS

i

Normally, the DHCP rate limit is specified to untrusted interfaces and 15 pps is recom- mended for a proper value. However, if you want to set a rate limit for trusted interfaces, keep in mind that trusted interfaces aggregate all DHCP traffic in the switch, and you will need to adjust the rate limit to a higher value.

8.8.7.4DHCP Lease Limit

The number of entry registration in DHCP snooping binding table can be limited. If there are too many DHCP clients on an interface and they request IP address at the same time, it may cause IP pool exhaustion.

To set the number of entry registration in DHCP snooping binding table, use the following command.

Command		Mode	Description
ip dhcp snooping	limit-lease		Enables a DHCP lease limit on a specified untrusted
			port.
PORTS <1-2147483637>
		Global	1-2147483637: the number of entry registration
no ip dhcp snooping limit-lease			Deletes a DHCP lease limit.
PORTS

You can limit the number of entry registration only for untrusted interfaces, because the

! DHCP snooping binding table only contains the information for DHCP messages from un- trusted interfaces.

8.8.7.5Source MAC Address Verification

The hiD 6615 S223/S323 can verify that the source MAC address in a DHCP packet that is received on untrusted ports matches the client hardware address in the packet.

To enable the source MAC address verification, use the following command.

Command	Mode	Description
ip dhcp snooping verify mac-address		Enables the source MAC address veri-
		fication.
	Global
no ip dhcp snooping verify mac-address		Disables the source MAC address veri-
		fication.

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