On your Trunk connection make sure to include all VLANs you want to be able to traverse that connection. So if you want both 100 and 101, then they will both need to be in the command.  #switchport trunk allowed vlan add 100,101 Trunk mode will be used when connecting the switch to the other network devices,  and access mode will be used to place an end device, like a workstation, into a specific VLAN.
Hello, Thismight be a very simple question; I just need to be sure that what I am doing iscorrect to avoid any negative consequences. AllI need to do is add a vLan that is segregated from the default vLan, users onthe new vLan cannot access the default vLan but can access the Gateway viaInterface 1. doesthis look right? interface ethernet g(01) switchport mode trunk exit vlan database vlan 101 exit interface ethernet g(39) interface switchport access vlan 101 exit interface ethernet g(1) switchport trunk allowed vlan add101 exit interface vlan 100 name Guest_Lan exit Inusing Access mode for the new vLan and using Trunk mode for the Gatewayinterface, is that correct or should I use Customer & General? Thanksin advance.  
vLan best practice