02-09-2013 11:17 AM - edited 03-03-2019 06:57 AM
I am preparing lab for CCNP Switch exam.
If I trace the packet , i found that ARP messages are passing from SwitchA to Switch B , but from SwitchB to SwitchA doesnt passes.
Host in SwitchB is no getting access to DHCP at router connected to SwitchA f0/1
SwitchB
show etherchannel summary
1 Po1(SU) LACP Fa0/3(P) Fa0/4(P) Po1(I)
SwitchA
show etherchannel summary
1 Po1(SU) LACP Fa0/3(P) Fa0/4(P)
below is my configuration
SwitchA
vtp domain DOMAIN
vtp mode transparent
!
spanning-tree mode rapid-pvst
spanning-tree vlan 11-13,21-23 priority 8192
!
vlan 11
!
vlan 12
!
vlan 13
!
vlan 21
name Marketing
!
vlan 22
name Sales
!
vlan 23
name Engineering
!
vlan 99
name TrunkNative
!
interface FastEthernet0/1 (connected with router )
switchport mode trunk
!
interface FastEthernet0/2 ( connected to a server which can get ip through DHCP in router)
switchport access vlan 21
switchport mode access
!
interface FastEthernet0/3
switchport trunk native vlan 99
switchport trunk allowed vlan 1,21-23,99
channel-protocol lacp
channel-group 1 mode active
switchport mode trunk
!
interface FastEthernet0/4
switchport trunk native vlan 99
switchport trunk allowed vlan 1,21-23,99
channel-protocol lacp
channel-group 1 mode active
switchport mode trunk
!
interface Port-channel 1
switchport trunk native vlan 99
switchport trunk allowed vlan 1,21-23,99
switchport mode trunk
!
interface Vlan1
no ip address
!
SwitchB
!
!
vtp domain DOMAIN
vtp mode transparent
!
spanning-tree mode rapid-pvst
!
vlan 21
name Marketing
!
vlan 22
name Sales
!
vlan 23
name Engineering
!
vlan 99
name TrunkNative
!
interface FastEthernet0/3
switchport trunk native vlan 99
switchport trunk allowed vlan 1,21-23,99
channel-protocol lacp
channel-group 1 mode passive
switchport mode trunk
!
interface FastEthernet0/4
switchport trunk native vlan 99
switchport trunk allowed vlan 1,21-23,99
channel-protocol lacp
channel-group 1 mode passive
switchport mode trunk
!
!
interface FastEthernet0/9
switchport access vlan 21
switchport mode access
spanning-tree portfast
!
interface FastEthernet0/10
switchport access vlan 21
switchport mode access
spanning-tree portfast
!
interface FastEthernet0/13
switchport access vlan 22
switchport mode access
spanning-tree portfast
!
interface FastEthernet0/14
switchport access vlan 22
switchport mode access
spanning-tree portfast
!
interface FastEthernet0/15
switchport access vlan 23
switchport mode access
spanning-tree portfast
!
interface FastEthernet0/16
switchport access vlan 23
switchport mode access
spanning-tree portfast
!
!
interface Port-channel 1
switchport trunk native vlan 99
switchport trunk allowed vlan 1,21-23,99
channel-group 1 mode passive
switchport mode trunk
!
interface Vlan1
ip address 192.168.1.11 255.255.255.0
!
ip default-gateway 192.168.1.1
!
Solved! Go to Solution.
02-09-2013 10:23 PM
Hi Irfan,
It looks like you have a wrong configuration on SwitchB. You dont put the channel group command under the actual port-channel interface itself. So please modify the configuraton as below and test the result for DHCP.
SwitchB
config terminal
interface Port-channel 1
no channel-group 1 mode passive
exit
Hope that helps
Regards
Najaf
Please rate when applicable or helpful !!!
02-09-2013 10:23 PM
Hi Irfan,
It looks like you have a wrong configuration on SwitchB. You dont put the channel group command under the actual port-channel interface itself. So please modify the configuraton as below and test the result for DHCP.
SwitchB
config terminal
interface Port-channel 1
no channel-group 1 mode passive
exit
Hope that helps
Regards
Najaf
Please rate when applicable or helpful !!!
02-10-2013 05:43 AM
Dear Najaf,
Great finding, IDHCP is working fine. Now i have a question Why LAB says make Switch B Interface port-cha 1 passive ?
02-10-2013 08:19 AM
Hi Irfan,
If the Lab says that you to make interface as passive then this configuration has to be applied on the physcial interface and not on the port-channel interface, which would then be applied to the actual port-channel interface.
Hope that helps.
Regards
Najaf
Please rate when applicable or helpful !!!
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