Question

IP address conflict detection on Extreme Layer 2 switches


Is there any logging feature on Extreme devices (switches or routers) that can detect IP address conflicts (in this case, on windows machines)?

3 replies

Userlevel 6
Hey Jimmy

The switch will detect a duplicate IP address by default and warn you if a station is set to the same IP Address of a VLAN. Using DHCP snooping helps this as it does not allow any static IP addresses on the network.

Also look at Duplicate Address Detection (DAD) in the concepts guide. It is on page 1255 of the 15.4 guide.

Hope that helps
P
Userlevel 4
IP DAD is a good feature.

We can also use UPM script to avoid duplicate ip in network.
It is quite common scenario to have protection for VRRP gateway to avoid network outage.

These commands are to be applied on edge switch .Core switch has VRRP.

configure log filter DupIP add events FDB.arpViolation create log target upm Disable_DupIP_Port
enable log target upm Disable_DupIP_Port
configure log target upm Disable_DupIP_Port filter DupIP severity Warning

enable ip-security arp gratuitous-protection vlan
enable ip-security arp gratuitous-protection vlan

UPM script

create upm profile Disable_DupIP_Port
set var up1 47
set var up2 48
## please specify the uplink ports as up1,up2..
if ($match($EVENT.LOG_PARAM_3,$up1) && $match($EVENT.LOG_PARAM_3,$up2)) then
disable port $EVENT.LOG_PARAM_3
create log entry "PORT $(EVENT.LOG_PARAM_3) WAS DISABLED DUE TO VRRP VIP CLASH"
endif
To fix ip address conflict, contact your ISP . After that, you can check your ip by using Ip-details.com

Reply