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Community Member

DHCP default-router

no ip dhcp conflict loggin

ip dhcp pool myDHCP

network 192.168.1.0 /24

default-router 192.168.1.254 192.168.1.250

right now, I want to know when the second gateway of 192.168.1.250 will work?

Thanks

2 REPLIES
Community Member

Re: DHCP default-router

The second gateway will work in the event the first gateway is unreachable.

The IP address of the default router should be on the same subnet as the client subnet. You can specify up to eight routers in the list. Routers are listed in order of preference (address1 is the most preferred router, address2 is the next most preferred router, and so on).

The following link provides more information on this command:

http://www.cisco.com/en/US/products/sw/iosswrel/ps1835/products_command_reference_chapter09186a0080087376.html#1017655

configuring DHCP:

http://www.cisco.com/en/US/products/sw/iosswrel/ps1835/products_configuration_guide_chapter09186a00800ca75c.html#xtocid14

Community Member

Re: DHCP default-router

Thanks for your reply.

Actually, I knew that. But I still have problem with it.

It seems easy, but not.

I give you my topology.

R1(dhcp server)

R2 and R3 connect to R1, between them, it is a WAN, maybe ATM,ISDN,DDN, or OSPF, eigrp, rip, etc.

and R2,R3 can ping R1

I configure "ip helper-address IPofR1" on R2 and R3.

E0 of R2 and E0 of R3 on the same subnet.

E0 R2, 192.168.0.2

E0 R3, 192.168.0.3

for the DHCP configuration of R1, I set the default-router like below

default-router 192.168.0.2 192.168.0.3

now, the PC in the subnet of 192.168.0.0 can get IP from DHCP server and the default-gateway is 192.168.0.2. everything is fine now.

I release the IP of PC and shutdown the E0 of R2.

Then I renew the IP of PC and the PC can still get the IP from dhcp server, but the default-gateway is 192.168.0.2 too, and the PC can not ping the 192.168.0.2, of course, can not ping the dhcp server, but the pc can ping 192.168.0.3

That is what I was confused.

Meanwhile, I am still confused if the second gateway work, what is the diffirent between HSRP and the DHCP? I think we don't need the HSRP, right?

Thanks

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