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Community Member

IP address for Vlan management over WAN

Our current network is flat, eveyone is in vlan1. I want to implement VLAN assignements on the 3500xl switches. Can you answer the following questions:

1. Setting up the management VLAN300, the main office is using non-public addresses. They did not subnet the addresses , they're using a mask. They want me to use vlan300 which is understandable but gave me a range of through with a we are in different georgraphical locations...Won't routing be confused? Shouldn'r subneting been applied per location?

2. Can anyone explain this configuration.

interface vlan300

ip address

ip nat outside


ip nat inside source list 199 interface vlan300 overload


access-list 199 dynamic CLuster-NAT permit ip any any

I don't know what it is doing? Explain please...

Community Member

Re: IP address for Vlan management over WAN

1. You are correct. By them giving you a mask of they have to use the range thru on this Lan only. The range .130 thru .200 doesn't even fall on any bit boundaries for subnetting, the closest is .128 thru .191 with a mask of

2. They are 'attempting' to do NAT (Network Address Translation). However, for this to work they need to have another interface that has the command "ip nat inside". Basically, the interface with the 'inside' whenever it talks out (ACL 199 permits ANYbody) the 'outside' interface it would appear to use the (overload) address as its source address.

If this was working properly you can issue a "show ip nat translation" and see which IPs are talking to the "outside".

Hope this helps,



Community Member

Re: IP address for Vlan management over WAN

Great, they gave me a new range 190 thru 255....subnetting this would make for a better design. At HQ, on the RSM they have an interface configured with the VLAN300...ip address x.x.x.28

This will create routing problems if at the new network I config

VLAN mgt config is:


ip address x.x.x.193 ......I MUST SUBNET, I am correct?

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