SG200-18 <-> C2960S trunked - SG200 cut off the net

[ewald.jenisch]

Hi,

Still trying to figure out how to connect our new SG200-18 to an existing Cisco network, in particular a C2960S.

Here's what I've got:

<----- Rest of network ------- C2960S ----------- SG200 ----- (PC connected directly to the SG200)

On the C2960S-side here's what I've got on the corresponding interface:

interface GigabitEthernet1/0/1

switchport mode trunk

On the SG200-side I've set the IP-address and default-gateway accordingly, however:

• From the SG200 I can't ping any other host on the same IP-subnet as the switch
• From the SG200 can't ping the default-gateway
• can't ping from any other host or the default-gateway *to* the switch

But:

• On the SG200 I've got plenty of MAC-addresses under "Dynamic Address Table" - however only MAC-addresses that belong to the management-VLAN of the SG200 (i.e. VLAN9 in my case)
• The MAC-address table on the SG200 even includes the MAC-addresses of hosts on the same VLAN I tried to ping without success. For example: I tried a PING from a host having a MAC-address of 00:19:bb:31:91:30. This MAC shows up in the arp table of the SG200.

To cross check I connected a dedicated PC to the SG200 and assign it an IP-address out of the management-LAN-range of the SG200 - in this case I can access the switch (i.e. PING, WEB etc.)

So to summarize:

• Connectivity is OK when going from directly connected devices to the SG200.

• No connectivity from devices that are behind the C2960S towards the SG200 and vice versa. (The problem is definitely not with the C2960S-side since we've got plenty of them hooked together without problems.)

I'm enclosing the screenshots of the corresponding definitions on the SG200.

Thanks much in advance for your help,

-ewald

[rocater]

Hi Ewald,

What is the port vlan settings for the C2960S? I see you mentioned that it is in trunk mode but it does not show a native vlan or allowed vlans.

[ewald.jenisch]

Hi Robert,

Yes, on the C2960S-side this is the only thing I've got:

interface GigabitEthernet1/0/1

switchport mode trunk

and here's what the config is like:

switch#sh int gig 1/0/1 switchport

Name: Gi1/0/1

Switchport: Enabled

Administrative Mode: trunk

Operational Mode: trunk

Administrative Trunking Encapsulation: dot1q

Operational Trunking Encapsulation: dot1q

Negotiation of Trunking: On

Access Mode VLAN: 1 (default)

Trunking Native Mode VLAN: 1 (default)

Administrative Native VLAN tagging: enabled

Voice VLAN: none

Administrative private-vlan host-association: none

Administrative private-vlan mapping: none

Administrative private-vlan trunk native VLAN: none

Administrative private-vlan trunk Native VLAN tagging: enabled

Administrative private-vlan trunk encapsulation: dot1q

Administrative private-vlan trunk normal VLANs: none

Administrative private-vlan trunk associations: none

Administrative private-vlan trunk mappings: none

Operational private-vlan: none

Trunking VLANs Enabled: ALL

Pruning VLANs Enabled: 2-1001

Capture Mode Disabled

Capture VLANs Allowed: ALL

Protected: false

Unknown unicast blocked: disabled

Unknown multicast blocked: disabled

Appliance trust: none

switch#

Hope this clarifies things a little.

TIA for your help,

-ewald

[rocater · Accepted solution]

It appears that you are using VTP with the switch. Unfortunately the SG200 does not support VTP.

You will have to set the port to match on both ends. This will be untagged vlan 9. If you plan to add more vlans at a later time, you will have to add both as tagged vlans on each switchport.

[ewald.jenisch]

Thanks alot - now at least I understand what went wrong in the first place with my config ;-)

-ewald