# A qustion about DAI packet tracer **URL:** \ **Category:** Security\ **Created:** [April 24, 2019, 1:12pm UTC](https://forum.networklessons.com/t/a-qustion-about-dai-packet-tracer/6922 "2019-04-24T13:12:20Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![orene10](https://cdn-forum.networklessons.com/letter_avatar_proxy/v4/letter/o/41988e/32.png) [@orene10](https://forum.networklessons.com/u/orene10)\ **Post date:** [April 24, 2019, 1:12pm UTC](https://forum.networklessons.com/t/a-qustion-about-dai-packet-tracer/6922/1 "2019-04-24T13:12:20Z")
Dear Rene’ I need your help please : Following the packet tracer of DAI in this further link : [https://networklessons.com/switching/dai-dynamic-arp-inspection](https://networklessons.com/switching/dai-dynamic-arp-inspection) , there is an important line : `SW1(config)#ip arp inspection vlan 123` however it is not working at all : I use a 7.2 version of packet tracer (the latest) , but the CLI show en error below the word arp. I wonder why. Please try to figure this out Thanks Oren ---
**Author:** ![lagapidis](https://cdn-forum.networklessons.com/user_avatar/forum.networklessons.com/lagapidis/32/4949_2.png) [@lagapidis](https://forum.networklessons.com/u/lagapidis)\ **Post date:** [April 30, 2019, 5:40am UTC](https://forum.networklessons.com/t/a-qustion-about-dai-packet-tracer/6922/2 "2019-04-30T05:40:48Z")
A post was merged into an existing topic: [DAI (Dynamic ARP Inspection)](https://forum.networklessons.com/t/dai-dynamic-arp-inspection/1296) ---
**Author:** ![lagapidis](https://cdn-forum.networklessons.com/user_avatar/forum.networklessons.com/lagapidis/32/4949_2.png) [@lagapidis](https://forum.networklessons.com/u/lagapidis)\ **Post date:** [April 30, 2019, 5:40am UTC](https://forum.networklessons.com/t/a-qustion-about-dai-packet-tracer/6922/3 "2019-04-30T05:40:48Z")