Passing Broadcast from 1 VLAN to another

[m-mneimneh]

Hi all,

Our sys admin is using a Sw delivery pkg; the pkg works by sending wake on lan packets using broadcast before delivering the pkgs; naturally, these broadcast pkts are not reaching other vlans. What can i do to make them do this?

thank you.

[m-mneimneh]

no man, i removed all ACLs & tried, with the same results.

on the other hand, i just found out that the magic packets go to 255.255.255.255, and not to say 172.16.111.255 {where the dst machine is}. i traced it using an ACL on the in direction of Vlan1 {where the server is}. after that point, nothing is showing up.

i found the following url: http://tcpmag.com/qanda/article.asp?EditorialsID=320

does this make sense?

-Mohamad.

[Richard Burts]

Mohamad

I believe that to solve your issue you will need both ip forward-protocol, ip helper-address and ip directed-broadcast commands. You will need the ip forward-protocol (which you seem to already have done), and the ip helper-address on the interface where the server is located. You will need to configure the helper address to point to the subnet broadcast of the remote VLAN (for example if the remote VLAN is subnet 172.16.4.0/24 then you would configure ip helper-address 172.16.4.255). And you need ip directed-broadcast on the remote VLAN interface.

You need the forward-protocol command to identify wake on LAN as a protocol to forward, and you need the helper-address to specify that it gets forwarded to the remote subnet as a subnet broadcast. You need the directed-broadcast on the remote VLAN interface because otherwise the interface will receive the forwarded packet but will not forward it onto the subnet.

HTH

Rick

[m-mneimneh]

Hi Rick,

indeed you are right! it's a combination of ip forward-protocol, ip directed-broadcasts & ip helper-address on the remote vlan. when i added the helper address, the machines woke up :)

thanks to all of you guys for your support.

-Mohamad.

[Richard Burts · Accepted solution]

Mohamad

Yes it is a combination of the 3 commands and of knowing which command needs to go on which interface.

I am glad that we were able to help you solve your problem. Thanks for the rating.

HTH

Rick

[Amit Singh]

Rick,

Well done, great answer.

Appreciate your knowledge and experience sharing with such wonderful posts.

Rated you Sir :-)

-amit singh

[Richard Burts]

Amit

Thank you for the kind words - and thanks for the rating. It means a lot to me to be able to help others by posting to the forum. And I appreciate having you as a long time active poster in the forum.

HTH

Rick

[mohammedmahmoud]

Hi Rick,

Its great learning from experts like your self.

BR,

Mohammed Mahmoud.

[Richard Burts]

Mohammed

Thank you for the kind words. I have spent a lot of time studying and gaining experience with many aspects of networking. I am happy to share with people through the forum. I am glad to see that you have become an active contributing member of the forum and I encourage you to continue your participation in the forum.

HTH

Rick

[tzverina]

Mohamad.

For the benefit of all involved, could you please post the completed final configs of the involved interfaces on both ends of the broadcast.

Thanks.

Thomas.