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I am confused with what happens to the default router adddress when we are configuring DHCP in the router.

I have the network with 253 hosts, 192.168.1.0/24, and I have configured DHCP in my network.

Now, while configuring DHCP, I have excluded the first four IP address of the network using ip dhcp exclude-address command, but I haven't excluded the address that I have used as a default-router address in DHCP configuration, which is the last address of the network, i.e. 192.168.1.254.

Now, I am confused that, since I didn't excluded that last ip address and point it to a default-router will router try to lease that address ?

If not, is it automatically excluded ? or do I have to exclude it myself to avoid any conflict ?

EDIT: default-router is pointing to another router where hosts are connected, and where ip helper-address is configured.

I am using 1841 Router in Packet Tracer.

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  • That depends on the router model. You should edit your question to include the router model. – Ron Maupin Nov 12 '15 at 3:08
  • hi, its 1841. and I am using Packet tracer. I have modified my question. Thanks – Riley Willow Nov 12 '15 at 3:11
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A Cisco ISR router like the 1841 excludes the router's address on the subnet for which DHCP is configured if the router is performing DHCP.

If you have two routers and an FHRP on the subnet, you need to be more careful.

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  • can you please tell me what is the best practice ? Is it recommended to always exclude default-router address no matter what the model is ? – Riley Willow Nov 12 '15 at 3:15
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    It won't hurt to exclude it. Whether or not you need to depends on the router and software. If your network is heterogeneous, you may want to do that as a best practice since it could be problematic to remember which routers require it, and which don't. – Ron Maupin Nov 12 '15 at 3:18
  • That's the answer I was looking for. :) Thanks heaps, now everything is clearer. – Riley Willow Nov 12 '15 at 3:25

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