UDP Broadcast thru of the routers

[lps05073]

I need send UDP broadcast DHCP thru of three routers.

My quesstion is if I need add IP HELPER ADDRESS in all routers or only in router source.

[DALE FRANCIS]

You should not have to at apply to all three devices only the 1st router the DHCP packet will hit.. also remember to use the ip forward udp 68 and 67

[lps05073]

Thank you...

[networksecurity]

Be sure to check out the following article on MS KB about all the UDP ports forwarded by IP HELPER ADDRESS.....it's not just DHCP. You need to block the other ones explicitly if you don't want them passing through as well.

http://support.microsoft.com/default.aspx?scid=kb;en-us;Q190930

Also:

http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/fipr_c/ipcprt1/1cfdhcp.htm