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VLAN Routing - NETBIOS Name

Hi, I have 4 VLANs as below;

VLAN1 - 192.168.1.x - a MS windows 2000 Domain Controller(D.C.), an Exchange Mail server and Firewall Proxy (ISA) also reside here.

VLAN2 - 192.168.2.x

VLAN3 - 192.168.10.x

VLAN4 - 192.168.20.x

All users in VLAN 1-4 needs to login to the D.C. in VLAN1 and access the shared files there and also checking mails from another exchange mail server. ISA Firewall in VLAN1 allows all VLAN users to surf Internet.

Q1) So how to solve the problem of NETBIOS (domain name) in order for all the VLAN users to login to the D.C. in VLAN 1 successfully?

Q2) For inter-VLAN routing, if I have a combination of 3COM switch, Cisco Switch and router,how can I perform the ISL encapsulation ???

Q3) Can I use the same subnet for two different VLAN ?

Anyone please help.

New Member

Re: VLAN Routing - NETBIOS Name

this will solve your problem,

conf t

int vlan 2

ip helper-address (Address of D.C.)

apply this to all the vlans.

New Member

Re: VLAN Routing - NETBIOS Name

Thanks a lot. I had the same problem than this person and thanks to your help I can have my lab working perfectly.

Re: VLAN Routing - NETBIOS Name


ad Q1)

should explain

ad Q2) ISL is Cisco proprietary, you need to use 802.1q as standard encapsulation between different vendors devices

ad Q3) This is strongly not recommended, very difficult to configure, dont use it. If it'a ABSOLUTELY necessary, you can use a special NAT configuration, see



Re: VLAN Routing - NETBIOS Name

Please give us some more details of the Switch Hardware you have and the software versions - 3COM Switch Cisco Switch and router doesn't really help.



Re: VLAN Routing - NETBIOS Name

I may be mistaken, but if you have Win2k Server and Win2k/XP clients, they don't use NETBIOS for locating the DC or resource location. These newer clients rely on DNS for resource location. If you have older NT clients or something, you could use a WINS server. Also as another poster pointed out, you can use the Cisco ip helper-address command to forward certain UDP broadcasts.


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