Refer to the exhibit. R4 is experiencing packet drop when trying to reach 172.16.2.7 behind R2. Which action resolves the issue?
Refer to the exhibit. R4 is experiencing packet drop when trying to reach 172.16.2.7 behind R2. Which action resolves the issue?
The issue is likely due to auto summarization being enabled. When auto summarization is enabled, the routers will advertise summary routes rather than the specific subnet routes. This can cause routing issues, especially with discontiguous networks. Since R4 is experiencing packet drops when trying to reach a subnet behind R2, disabling auto summarization on R2 will ensure that R2 advertises the specific subnet routes rather than summarizing them. This should resolve the packet drop issue.
/24 static route is more specific than /16 route, so it will be chosen even if the AD is 254
With auto-summary enabled, subnets will be advertised as classful networks. This causes problems with discontiguous networks. R2 will think it has two equal paths (via R1 and R3) to reach 172.16.0.0/16. https://networklessons.com/eigrp/eigrp-auto-summary
This is supposed to be A, the /24 prefix is being sent to R2 by its neighbours, the only way it will route properly to the desired /24 prefix is to create a route with a longer prefix. This takes precedence over the current summarized route in the routing table
Indeed, R2 will receive a summarized route, so B will not be able to undo this.
I checked https://networklessons.com/cisco/ccie-routing-switching/eigrp-auto-summary and for sure the answer is A (!) here. Disable auto summary only works on the routers that actually advertise the routes initialy.
i believe its a /16 thats currently in the routing table, even with a 172.16.0.0 /24 route, the router is still not aware of the existence of the interesting route, so creating the route is still valid
it´s A
Actually I have labbed it, If you disable auto summarization in R2 nothing seems to change, you will advertise the routes from the other routers has they are. It auto summarization was active in all the network I should receive a 172.16.0.0/16 network. In this case I think that the router is not receving the specific routes via EIGRP, so we need to configure a static route for fix the problem as soon as possible
R2#show running-config | sec router eigrp router eigrp 1 network 10.0.0.0 auto-summary R2#show ip route eigrp 172.16.0.0/24 is subnetted, 2 subnets D 172.16.1.0 [90/409600] via 10.1.1.1, 00:06:02, Ethernet0/1 D 172.16.2.0 [90/409600] via 10.1.2.1, 00:06:07, Ethernet0/0 R2#
Its better to be specific on situations like this in order to not have packets destined for one address, (172.16.1.0) and have it go instead to another address. (172.16.2.0) Therefore, disabling summarization would be needed for packets to go to their intended destination.
Never mind, I read the question too fast. I CHOOSE "A" due to R2 being advertised summary routes. Adding the floating static route would fix the issue to then have packets go to their intended destination.