C3750G-16: No route to specific subnet, while route to individual addresses works

[alexilookin68]

Hello there!

I have Catalyst C3750G switch

with configured route to subnet 192.168.201.0/24

ip routing

ip route 192.168.201.0 255.255.255.0 192.168.160.13

192.168.160.13 is accessible

sw12-3750G-TD16-1#ping 192.168.201.82

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.201.82, timeout is 2 seconds:

.....

Success rate is 0 percent (0/5)

sw12-3750G-TD16-1#

but if add the next line this node starts respond

ip route 192.168.201.82 255.255.255.255 192.168.160.13

sw12-3750G-TD16-1#ping 192.168.201.82

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.201.82, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/3/8 ms

sw12-3750G-TD16-1#

what is problem? please, help

Sincerely, Alexey

[cadet alain]

Hi,

to decide which entry to use  in the RIB to forward a packet the router chooses the longest match.

Can you provide output of sh ip route 192.168.201.0 255.255.255.0 before configuring the host route.

Regards.

Alain

[Vivek Ganapathi]

Alain is right. Just to add, there is a chance that you may already have a longest match route pointing to another gateway. May be something like this

ip route 192.168.201.0 255.255.255.128 X.X.X.X

X.X.X.X could be some other gateway.

your show show ip route output may provide the answer. Will wait.

Thanks

Vivek

[alexilookin68]

sw12-3750G-TD16-1#sh ip route 192.168.201.0

Routing entry for 192.168.201.0/24, 3 known subnets

  Attached (2 connections)

  Variably subnetted with 2 masks

C        192.168.201.0/24 is directly connected, Vlan10

L        192.168.201.12/32 is directly connected, Vlan10

S        192.168.201.82/32 [1/0] via 192.168.160.13

I forgot mention one thing: this switch had  vlan 10 with 192.168.201.12 address, if remove vlan 10 with its address from 3750G, ping works as it should: it pings all VLAN nodes in 201.0

!

interface Vlan10

ip address 192.168.201.12 255.255.255.0

!

[cadet alain]

Hi,

if the /24 is a connected route then it will have an AD of zero and it will win against the static route with an AD of 1

Can you provide a diagram explaining what you are doing.

Regards.

Alain

[alexilookin68]

Yes, i will prepare all materials and descriptions at Monday.