By accident I had configured an IP HELPER-ADDRESS on a VLAN interface pointing to a DHCP server with an IP addrees in the same VLAN ( ip subnet ).
Some users had complaints and there were BAD ADDRESS entries in our DHCP server registered.
Can anyone explain to me why this is an issue please ?
My guess is that the the DHCP server receives the DHCPREQUEST from the client via the braodcast request and via the unicast request from the ip helper-address configuration. But does this really interfere with the DHCPACK and DHCPOFFER packets afterwards ?
First of of all you no need to have ip-helper address configured on the vlan interface where both dhcp and interface is in same subnet. You need to configure ip-helper address when your dhcp server is in different subnet.
So please remove the ip-helper command to fix your issue.
Please rate all the helpfull posts. Regards, Naidu.
I've not been able to capture the network packets but I can understand if the server would send DHCPNACK requests ( wxhich would be a normal process ).
I just don't understand why so many users suddenly have issues and my DHCP scope is filling up with BAD ADDRESSES.
My assumption is that the client receives 2 valid DHCP responses ( one form the actual DHCP server and another one from the router, acting as DHCP relay agent ) and acknowledges them, but the DHCP process is somewhere corrupted ( either on the DHCP server or the DHCP client ).
Assuming that I have a multi vlan site with a Windows DHCP dishing out IPs. I have the IP helper command on the right int vlans. How should I configure the port where the DHCP windows server is connected?
This is actually a pretty cool feature, i didn't even know it existed until I was looking for a solution to advertise a subnet (prefix in BGP talk), only if a certain condition existed. This is exactly what conditional advertisements does
j ai une question j ai achete un routeur cisco 887VA-k9 , je le configuré avec la configuration ci- dessous
si je le lier avec mon pc portable sur l un de ses ports directement ça marche toute est bien ( la connexion internet + m...
Attached policy provides CLI access to the Cisco 4G router over text messaging. Two files are in the attached .tar file:
2. PDF with instructions on how to load and use the .tcl file.