[Cisco] DHCP snooping Test

test Environment: a dhcp Server that has DHCP configured  , one Cisco switch (iOS version: 12.4), two PCs.

topology Diagram for illustration:1-1.

Test Purpose:Cisco switches turn on DHCP  snooping function, all default ports are required for DHCP Server and PC corresponding port setting DHCP  snooing Trust.

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Fig.:1-1

Test steps:

1. enable D on SwitchHCPsnooping  , the VLAN1 join to snooping, other interfaces G0/1,f0/1,f0/2 do not do IP  DHCP snooping Trust configuration, view two PCs can getto the correctof theIPaddress.

S witch:

Switch #config T

switch (config) # IP DHCP snooping // turn on DHCP snooping

switch (config) #ip DHCP snooping VLAN 1 // the VLAN 1 join to DHCP snooping

Both PCs cannot obtain an IP address.

2. enable D on SwitchHCPsnooping  , the VLAN1 join to snooping, other interface G0/1 do IP  DHCP snooping Trust configuration, view Two unitsPCcan I get the the right IPaddress.

S witch:

Switch #config T

switch (config) # IP DHCP snooping // turn on DHCP snooping

switch (config) #ip DHCP snooping VLAN 1 // the VLAN 1 join to DHCP snooping

switch (config) # int Range G0/1

Switch (config) #ip DHCP snooping Trust

Both PCs cannot obtain an IP address.

3. enable D on SwitchHCPsnooping  , the VLAN1 added to snooping, other interfaces G0/1,f0/1 ,F0/2 on do IP  DHCP snooping Trust configuration, view Two unitsPCcan I get the the right IPaddress.

S witch:

Switch #config T

switch (config) # IP DHCP snooping // turn on DHCP snooping

switch (config) #ip DHCP snooping VLAN 1 // the VLAN 1 join to DHCP snooping

switch (config) # int range G0/1, F0/1–2

Switch (config) #ip DHCP snooping Trust

Both PCs can obtain the IP address.

Summary: need to be in the DHCP Server the switch port corresponding to the PC is set to DHCP snooping Trustso that the PC Get the right IP address.

This article is from the "tommyking" blog, make sure to keep this source http://tommyking.blog.51cto.com/10481841/1916537

[Cisco] DHCP snooping test