Wake on LAN across a corporate environment

[Andrew Reid]

                   I have a requirement to setup wol in an environment where there are about 8 sites all connected on a private MPLS.

Each site has 20 - 50 PC's on it. I have been asked to configure the Cisco equipment to allow from a single place the ability to wake any PC at any office.

I have looked at various documents on the Cisco website, but I'm still not quite sute. Has anyone done this already in the past??

I could do with an idea of what will be required at each office WAN router. Thanks

[Richard Burts · Accepted solution]

Andrew

I have configured WoL in an environment somewhat similar to what you describe. Based on my experience here is my advice about what you need to do.

- start on the router connecting the subnet where the WoL source is located.

- determine what protocol port number is to be used for WoL.

- configure an ip forward-protocol to match that protocol port.

- configure an ip helper-address for every remote subnet which needs to receive WoL. (this is the most tedious of the steps since you need one per remote subnet)

- then on each remote router where WoL will be received configure an ip directed-broadcast on each interface where clients are connected that will receive WoL.

Depending on how concerned you are with security issues you may want to make use of the optional capability to configure an access list to control the directed broadcast to limit it to WoL.

In summary

- you need an ip forward-protocol statement to match the protocol port that will be used for WoL (frequently it is port 6 but depending on the server it might be something different).

- you need an ip helper-address configured on the source subnet for each destination subnet to forward the WoL as a broadcast to the remote subnet.

- you need an ip directed-broadcast on each remote subnet to permit forwarding of the WoL packet onto the subnet as a broadcast.

HTH

Rick

[Andrew Reid]

Thanks for the information.

So to just understand fully. Assuming udp 9 used to a remote router with an internal interface 192.168.10.1. and clients all 192.168.10.x

On central site where wol software is running

ip forward-protocol udp 9

Central site under interface where wol software is running

ip helper-address 192.168.10.255

Remote site

under interface where remote PC's are

ip directed-broadcast

[Andrew Reid]

One other thing, this wakes the entire remote LAN's PC's. If I wanted to only wake certain PC's would I need an ip helper address at the main site for each PC's address?

[Richard Burts]

Andrew

You have a correct understanding of these points. The configuration that you suggest should work. And if you want to wake only certain PCs then you would need a helper-address configured for each host address.

HTH

Rick

[Andrew Reid]

Thanks for taking the time to help.

Andy

http://www.watersystems4u.co.uk

[Richard Burts]

Andy

I am glad that my response was able to resolve your questions. Thank you for using the rating system to mark this question as resolved. It makes the forum more useful when people can read a question and can know that an answer was received. Your marking has contributed to this process.

HTH

Rick

[Andrew Reid]

Rick, sorry another question.

I need to forward port 9 and 12287

When I enter the command ip forward-protocol udp 9

I then do a show run and it shows as ip forward-protocol nd

Is that ok?

Thanks

[Richard Burts]

Andy

You are certainly welcome to ask another question.

I do not think that it is ok. I am about 99% sure that the ip forward-protocol nd was already in the config before you started making changes and is one of the things that Cisco has put into the running config.

The command as you have written it in your post looks correct. But if it had taken I would expect it to show up in running config. If it is not showing up then I believe that something is not right. Perhaps you could try it again using this approach.

- to start enter the command terminal monitor

- then configure terminal

- then ip forward-protocol udp 9

- then end

- then show run | inc udp

and then copy and paste the output from your terminal session to this thread.

HTH

Rick

[Andrew Reid]

I had a bit of messing about with this yesterday were it was giving me the discard below. When I removed that line with a no, I got the nd.

RTR001(config)#do sh run | i udp

ip forward-protocol udp 12287

permit udp any any eq bootps

permit udp any any eq bootpc

permit udp any any eq bootps

permit udp any any eq bootpc

RTR001(config)#

RTR001(config)#

RTR001(config)#

RTR001(config)#

RTR001(config)#ip forwar

RTR001(config)#ip forward-protocol udp 9

RTR001(config)#do sh run | i udp

ip forward-protocol udp 12287

ip forward-protocol udp discard

permit udp any any eq bootps

permit udp any any eq bootpc

permit udp any any eq bootps

permit udp any any eq bootpc

RTR001(config)#ip forward-protocol udp 9

RTR001(config)#do sh run | i udp

ip forward-protocol udp 12287

ip forward-protocol udp discard

permit udp any any eq bootps

permit udp any any eq bootpc

permit udp any any eq bootps

permit udp any any eq bootpc

[Richard Burts · Accepted solution]

Andy

This is actually the expected behavior. The explanation is that UDP port 9 is for the discard service. So you input the command specifying the numeric value and the IOS is displaying the service name. You would get similar results if you input tcp port 23 and IOS would display telnet.

This URL shows the various port numbers and the services associated with each. In it you can clearly see that UDP port 9 is associated with discard.

http://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xml

So if your WoL is going to use UDP port 9 then the command that you are using should make it work.

HTH

Rick

[Andrew Reid]

Thanks again.

[UmairMk]

I have implemented that recently and worked with ip helper command within  the interface vlan and ip forward-protocol udp discard globally.