09-20-2007 07:54 AM - edited 03-05-2019 06:36 PM
We run an all cisco network wth a 6500 core switch and 3500 access layer switches.
In one instance a customer had a VOIP gateway device plugged in improperly and as a result all clients on that specific VLAN looses their regularly assigned IP address and picks up on from the VOIP Gateway which is setup to be a DHCP server.
Is there anything that can be doneto prevent unauthorized DHCP servers from causing outages such as these?
09-20-2007 07:59 AM
Hi
The newer switches have a feature called dhcp snooping which prevents unauthorised DHCP servers taking out your network. Unfortunately I don't believe that your legacy 3500 switches will have support for this feature.
Details on dhcp snooping can be found here:
09-20-2007 08:05 AM
TBH I don't think there is much you can do from where you are. As mentioned, DHCP snooping may help, but another aspect to consider - How big are your subnets? Smaller subnets would mean fewer users would be affected by an incident like this.
09-20-2007 08:46 AM
Thanks to both of you for your responses.
I realize this may be the case however I wanted to be certain.
I will read up on DHCP snooping and find out what I would need to put in place to mitigate incidences as these.
Thanks again.
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