# VLAN Hopping **URL:** https://forum.networklessons.com/t/vlan-hopping/1297 **Category:** Lessons Discussion **Created:** [December 29, 2016, 8:17pm UTC](https://forum.networklessons.com/t/vlan-hopping/1297 "2016-12-29T20:17:38Z") **Posts on this page:** 1 **Showing post:** 2
### Author: ![aelwahid](https://cdn-forum.networklessons.com/letter_avatar_proxy/v4/letter/a/977dab/32.png) [@aelwahid](https://forum.networklessons.com/u/aelwahid) #### Post date: [October 8, 2015, 2:04pm UTC](https://forum.networklessons.com/t/vlan-hopping/1297/2 "2015-10-08T14:04:12Z")
Dear René, Thank you very much for this great job ! I have a couple of questions about double tagging : To be effective and exploited, this attack means that the attacker frame is not already in a port with a vlan other than the native vlan ? In this sentence : “When the switch receives the frame, **it will remove the first 802.1Q tag** and forwards the frame with the second 802.1Q tag on its trunk interface(s).” Why the switch remove the first tag when this one " enter " the trunk ? Removing tags occurs when the frame exit the trunk for being delivered to the destination host ? Isn’t it ? If it is a " native vlan " does the switch remove the tag at the entry of the trunk ? We use the native vlan to specify untagged frames ? To be honest, not very clear for me 🙂 Prince --- _[View the full topic](https://forum.networklessons.com/t/vlan-hopping/1297)._