Changing OSPF areas causing DHCP failure.

[ahmadqayyum7]

At first I kept the OSPF area same i.e. 0. Then for each router I changed the area. For R0 R1 R2 R3 R4 i gave area 0 1 2 3 0 respectively. Now the PCs attached with R4 are failing in getting DHCP IP addresses. What have I done wrong?

Also can you modify it so that same areas don't repeat for different routers.

[Giuseppe Larosa]

Hello,

>> For R0 R1 R2 R3 R4 i gave area 0 1 2 3 0 respectively. Now the PCs attached with R4 are failing in getting DHCP IP addresses. What have I done wrong?

OSPF requires that all non zero areas connect to area 0 and that area 0 can be only one and must be formed by devices connected by links in area 0.

Try the following:

put R0 in area 1

put R0-R1 link in area 1

make R1 an ABR router for area (0,1) with R0-R1 link in area 1

have R1-R2 links in area 0

R2 in area 0

R3 will be ABR (0,2)

R3 link to R4 in area 2, all other links in area 0

R4 in area 2

This way you have a valid OSPF multiple area design and it should work.

Area 1 --- area 0 ---- area 2

This is correct

Hope to help

Giuseppe