Can't Reach Remote Host From Other VLANs on Core Switch

[Dan Man]

I'm a bit lost this morning.  I have a layer 3 core switch stack at one of my sites that has around 10 VLAN's.  Each VLAN has its own layer 3 SVI.  One of the VLAN's is my transit VLAN to my WAN.  Let's say that transit vlan is vlan 100 with the SVI as 10.10.100.1/24, and the directly connected layer 3 router inside interface is 10.10.100.4/24.  My default route, on the core switch is 0.0.0.0/0 10.10.100.4.  I'm trying to ping a remote host(let's say the remote host is 10.20.100.20), within our MPLS network.  I can ping this host with no issue, from the transit vlan on the core switch.  However, I have other VLAN's, on this core switch, and they cannot ping the same remote host when sourcing from them.  For instance, when I try ping 10.20.100.20 source 10.10.90.1), it fails.  From the remote host, I can ping the 10.10.100.4 and the 10.10.100.1 with no issue, but can't ping the other VLAN SVI's from this remote host.  Any ideas?  Thanks!

[Deepak Kumar]

Hi,

Can you check routes are added on the router as well for all your other VLANs?

Regards,

Deepak Kumar

[Dan Man]

Good morning!  Thank you for your reply!  Yes, the first thing I checked was the routes on the router.  Since this site was given the 10.10.0.0/16 network, I have a route, on the router, that points the 10.10.0.0/16 to the inside directly connected interface IP(10.10.0.0/16 10.10.100.1)

[Deepak Kumar]

Hi,

Please share "Show IP Route" & "Show IP access-list" commands output from router and switch.

Regards,

Deepak Kumar

[Dan Man]

From core switch:

S*   0.0.0.0/0 [1/0] via 10.10.100.4

     10.0.0.0/8 is variably subnetted, 20 subnets, 2 masks

C       10.10.10.0/24 is directly connected, Vlan10

L       10.10.10.1/32 is directly connected, Vlan10

C       10.10.20.0/24 is directly connected, Vlan20

L       10.10.20.1/32 is directly connected, Vlan20

C       10.10.30.0/24 is directly connected, Vlan30

L       10.10.30.1/32 is directly connected, Vlan30

C       10.10.40.0/24 is directly connected, Vlan40

L       10.10.40.1/32 is directly connected, Vlan40

C       10.10.50.0/24 is directly connected, Vlan50

L       10.10.50.1/32 is directly connected, Vlan50

C       10.10.60.0/24 is directly connected, Vlan60

L       10.10.60.1/32 is directly connected, Vlan60

C       10.10.70.0/24 is directly connected, Vlan70

L       10.10.70.1/32 is directly connected, Vlan70

C       10.10.80.0/24 is directly connected, Vlan80

L       10.10.80.1/32 is directly connected, Vlan80

C       10.10.90.0/24 is directly connected, Vlan90

L       10.10.90.1/32 is directly connected, Vlan90

C       10.10.100.0/24 is directly connected, Vlan100

L       10.10.100.1/32 is directly connected, Vlan100

No ACL's on the core switch or on the router.   The router has the following route:

ip route 10.10.0.0/16 10.10.100.1 name Internal_LAN

[Deepak Kumar]

Please share routing table output. It is not compulsory, if you configured any route then it will initialize in the routing table.

[Julio E. Moisa]

Hi,

Is this subnet advertised into the MPLS network? Can you see them into the routing table on the CE router?

[Dan Man · Accepted solution]

You sir, are correct!!!  Fortunately, we have read access to our MPLS routers.  I went in there and looked at the BGP table, and did not see these networks!  Although we had a ticket that requested the static route be added to our headend MPLS router(since we backhaul our traffic), the route was never added, so the redistribute static didn't pick up the route!!  Thank you so much!

[Julio E. Moisa]

Great! It must be advertised into MPLS

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:-)