Duplicated IP interface on the same subnet when configuring port-channel (L3)

ptoumbas2011 · ‎12-11-2014

Hi, I am trying to configure port-channel on SG300 L3 switch. When i try to assign an ip to the interface i get the following error:

Sw2Fl4(config-if)#ip address 192.168.2.16 255.255.255.0

Duplicated IP interface on the same subnet.

The management ip of the switch is in the same subnet (192.1682.10). Why it wont let me to have another IP assigned to another interface? Olny 1 interface can use an ip form the same subnet? Below is my current config :

config-file-header
switchcf920f
v1.3.7.18 / R750_NIK_1_35_647_358
CLI v1.0
set system mode router

file SSD indicator encrypted
@
ssd-control-start
ssd config
ssd file passphrase control unrestricted
no ssd file integrity control
ssd-control-end cb0a3fdb1f3a1af4e4430033719968c0
!
spanning-tree bpdu filtering
vlan database
vlan 100,200
exit
voice vlan oui-table add 0001e3 Siemens_AG_phone________
voice vlan oui-table add 00036b Cisco_phone_____________
voice vlan oui-table add 00096e Avaya___________________
voice vlan oui-table add 000fe2 H3C_Aolynk______________
voice vlan oui-table add 0060b9 Philips_and_NEC_AG_phone
voice vlan oui-table add 00d01e Pingtel_phone___________
voice vlan oui-table add 00e075 Polycom/Veritel_phone___
voice vlan oui-table add 00e0bb 3Com_phone______________
bonjour interface range vlan 1
hostname switchcf920f
line console
no autobaud
exit
!
interface vlan 100
name Management
ip address 192.168.2.10 255.255.255.0
!
interface vlan 200
name Guest
!
interface gigabitethernet1
switchport mode access
switchport access vlan 100
!
interface gigabitethernet2
switchport mode access
!
interface gigabitethernet3
switchport mode access
switchport access vlan 100
!
interface gigabitethernet4
switchport mode access
switchport access vlan 100
!
interface gigabitethernet7
switchport mode access
switchport access vlan 100
!
interface gigabitethernet8
switchport trunk allowed vlan add 200
switchport trunk native vlan 100
!
interface gigabitethernet9
switchport mode access
switchport access vlan 100
!
interface gigabitethernet10
switchport mode access
switchport access vlan 100
!
interface gigabitethernet11
switchport mode access
!
interface gigabitethernet15
switchport mode access
switchport access vlan 100
!
interface gigabitethernet16
switchport trunk allowed vlan add 200
switchport trunk native vlan 100
!
interface gigabitethernet17
switchport mode access
switchport access vlan 200
!
interface gigabitethernet18
no negotiation
no spanning-tree portfast
!
interface gigabitethernet19
switchport mode access
switchport access vlan 100
!
interface gigabitethernet20
no negotiation
no spanning-tree portfast
!
interface Port-channel1
description SW
!
exit

Please advise. Thank you

Kind regards

Petros

Henrik Grankvist · ‎12-11-2014

The switch is correct, listen to it! :)

You are trying to create a new broadcast domain, with the same IP address as another broadcast domain, on the same device. It would be the same as you were trying to configure VLAN 200 with IP address of 192.168.2.20. That would not work either.

What you should do is to create a layer 2 port-channel and assign it to VLAN 100 or continue creating a layer 3 port-channel and assign an IP address of a different subnet.

ptoumbas2011 · ‎12-11-2014

Thank you Henrik for the reply,

It was my mistake not to think of it earlier. I have already configured my etherchannel using L2 ports, as i have found it more appropriate based on the company needs. All ports are trunked and assigned to same channel-group. Port-channel was automatically created for L2 as well.

Thank you