topic RE: ARP requests from Extreme Stack in ExtremeSwitching (EXOS/Switch Engine)

ARP requests from Extreme Stack

jasonlsch — Thu, 13 Dec 2018 04:00:00 GMT

Hi,

Is it normal for Extremes to send out ARP requests to subnets not in use?

19935 2018-12-12 13:49:48.868077000 MS-NLB-PhysServer-04_96:36:1e:ac Broadcast ARP 60 Who has 10.108.251.35? Tell 10.108.0.1

We do not use 10.108.251.x

Can I tell switches to only ARP subnets we use?

Thanks.

RE: ARP requests from Extreme Stack

jasonlsch — Thu, 13 Dec 2018 04:19:00 GMT

It looks like it's running thru entire 10.108.x.x subnet?

22 2018-12-12 13:48:46.791238000 MS-NLB-PhysServer-04_96:36:1e:ac Broadcast ARP 60 Who has 10.108.246.95? Tell 10.108.0.1

10179 2018-12-12 13:48:54.390224000 MS-NLB-PhysServer-04_96:36:1e:ac Broadcast ARP 60 Who has 10.108.247.19? Tell 10.108.0.1

13566 2018-12-12 13:49:10.443917000 MS-NLB-PhysServer-04_96:36:1e:ac Broadcast ARP 60 Who has 10.108.248.84? Tell 10.108.0.1

15453 2018-12-12 13:49:21.492526000 MS-NLB-PhysServer-04_96:36:1e:ac Broadcast ARP 60 Who has 10.108.249.33? Tell 10.108.0.1

17765 2018-12-12 13:49:35.804269000 MS-NLB-PhysServer-04_96:36:1e:ac Broadcast ARP 60 Who has 10.108.250.88? Tell 10.108.0.1

19935 2018-12-12 13:49:48.868077000 MS-NLB-PhysServer-04_96:36:1e:ac Broadcast ARP 60 Who has 10.108.251.35? Tell 10.108.0.1

It doesn't seem like it's necessary. Can I stop this? Only ARP subnets we use?

Thanks

RE: ARP requests from Extreme Stack

AdrianO — Thu, 13 Dec 2018 15:27:00 GMT

Maybe you have declared 10.108.0.1/16 instead of 10.108.0.1/24

RE: ARP requests from Extreme Stack

jasonlsch — Thu, 13 Dec 2018 23:10:00 GMT

It looks like we are using 10.108.0.1/16:

"configure vlan Desktops ipaddress 10.108.0.1 255.255.0.0
enable ipforwarding vlan Desktops"

We use:
10.108.0.x
10.108.200.x
10.108.201.x

This was setup before my time. If I wanted to eliminate this excessive ARP would this work? Setup 10.108.200.1/24. I'm using about 200 IP addresses in 10.108.x.x. Re-IP the 10.108.0.x devices...

"configure vlan Desktops ipaddress 10.108.0.1 255.255.254.0
enable ipforwarding vlan Desktops"

Thanks

RE: ARP requests from Extreme Stack

AdrianO — Thu, 13 Dec 2018 23:25:00 GMT

I think its more efficient to do 10.108.0.1/24 and another vlan 10.108.200.1/23, less work

RE: ARP requests from Extreme Stack

jasonlsch — Thu, 13 Dec 2018 23:34:00 GMT

forgive my ignorance but...

Should I create a new VLAN? Desktops1, and do following:

"configure vlan Desktops ipaddress 10.108.0.1 255.255.255.0
enable ipforwarding vlan Desktops"
"configure vlan Desktops1 ipaddress 10.108.200.1 255.255.254.0
enable ipforwarding vlan Desktops"

Thanks

RE: ARP requests from Extreme Stack

AdrianO — Thu, 13 Dec 2018 23:51:00 GMT

Yeah, but I didnt thought about the devices configuration, you still have to change the gateway in all of them. Sorry.

Maybe there is another solution.

RE: ARP requests from Extreme Stack

AdrianO — Thu, 13 Dec 2018 23:52:00 GMT

youd have to change gateway and mask of course

RE: ARP requests from Extreme Stack

jasonlsch — Thu, 13 Dec 2018 23:56:00 GMT

Thanks