1 subnet 1 vlan

**Haleema** · 23-07-2011

Most excellent practice dictates that a VLAN is equal to a subnet. I understand the logic behind it, nevertheless I cannot assist other than wonder what happens if you alter that situation. Can a VLAN cover multiple subnets plus at a stop the progress of function normally? If so, what happens through the side of a level switch? ARP will motionless determine the addresses of the link layer for dissimilar subnets? I know it's an awkward question to ask, especially since I'm finishing my CCNP switch, nevertheless I think no one has tried this in my understanding material.

**Nipmuc** · 23-07-2011

From time to time doing this. For example we have a management VLAN of the directions to each switch. However rather than squander a VLAN when we only require transportation to use static routes to send traffic through a VLAN. It seems to work well for us.hat totally defeats the point of having a management VLAN / address space. It's the identical subnet and discontinues wasting your team just standard IP subnets.

**Ojibwe** · 23-07-2011

We have a new client comes on board. I built the infrastructure of the office later reported only with existing servers / "things" moving on. The management is worrying about breaking "things", so a temporary solution that has set up a "secondary" address to your new office subnet SVI will be responsible for communicating their old network without routing. Then, when the people around him can migrate data or devices in the range of new directions and require thumbs down network configuration to us. It's just the expediency of the question not actually the most excellent practices. Furthermore, DHCP is screwed if you forget to deactivate the existing server, it would be fun. May be I will configure the switch ports to disable DHCP.

**Sabastiaan** · 23-07-2011

However, each host on each subnet ARP for the devices on each subnet. If you have this multi-network all subnets take delivery of the ARP broadcasts either subnet, although if you desire to access a subnet 2 subnet, then you need a router, and hosts to talk to your default gateway. Unless each team had a secondary address on another subnet. You can configure a secondary address on a router-on-a-stick and make the route between the two subnets. Switches more often do not care about the networks change.

**Pennacook** · 23-07-2011

Code:

arp -s 192.168.0.1 0000.0c07.ac01
route add 192.168.0.1 dev eth0
route add default gw 192.168.0.1

It should work. As long as you have the address of l2 is local and knows that they are good

**Nipissing** · 23-07-2011

When converting a VLAN from one subnet to another, often use secondary IP addresses. The router will happily route flanked by two different subnets on the same physical plus logical interface secondary address when participating. We establish with something like:

Code:

interface Fa0
ip address 192.168.

1.1 255.255.255.0
add: 172.16.0.1/24,

Code:

int Fa0
ip address 172.16.0.1 255.255.255.0 secondary

Then we'll move the individual hosts and/or update the DHCP server, then run:

Code:

int Fa0
ip address 172.16.0.1 255.255.255.0

To get rid of high school and complete the transition. It works very well to diminish downtime. Outstanding to proxy Arp is not a requirement that the entrance will be on the identical subnet as the host. It is rarely used, so you could pre-populate the form and let the right thing for the rare occasions when your default gateway is not local, but if it is prevented, which would break a fraction of users who need this functionality. Not that a small group, since this technique is often used for dial-up PPP.