Dhcp Server & VRRP OS9907

[Zanade90]

Hello everybody,

I have 2 core switch os9907, vrrp already configured, and i wanted to create an internal dhcp server, the question is: is there any specific configuration for the creation of the dhcp server, or only i have to create it in the two switches ?


Best Regards. 

[silvio]

You can activate at the two switches the dhcp server at the same time. But be aware that also the dhcp at the vrrp backup is active. So the best way is to create at one the first part of the ip range and at the other one the second.
best regards
Silvio

[Gleylancer]

That sounds like a very dirty solution, having two active DHCP Servers on the same network may cause all sorts of unwanted effects. A client may be forced to switch its IP if a NAK packet is faster than an ACK as a response to a request. This will cause network interruption for that client.

My advice is to run a DHCP Server somewhere else.

[Zanade90]

You can activate at the two switches the dhcp server at the same time. But be aware that also the dhcp at the vrrp backup is active. So the best way is to create at one the first part of the ip range and at the other one the second.
best regards
Silvio

Thanks Silvio for your answer, i have configured it as your proposition, but i see that it takes about 20 seconds for a client to get an address, is that ok, or it's too long ?

Thanks.

[silvio]

20 seconds are a very long time. Not sure about the reason. You have to find out with wireshark of all the dhcp packet.
Important is to use different ip ranges within the same subnet.
dhcp-relay has to be not used if dhcp-server is active.
But like Gleylancer has written: also my prefered solution is to use an other server as dhcp (f.e. windows server) and activate dhcp-relay
best regards
Silvio

[Gleylancer]

Thanks Silvio for your answer, i have configured it as your proposition, but i see that it takes about 20 seconds for a client to get an address, is that ok, or it's too long ?

This may just be one of those undesired effects, I imagine that the wireshark trace shows a storm of Requests, Offers and NAKs, confusing the client for some time until the packets randomly arrive in the correct order.

Please abandon implementing such a dirty solution immediately. Any windows server and any firewall or router is a much better choice than this abomination.