Unable to ping my switch

[Deanna Wetzel]

Hello,

Been struggling with this a while.  I have a 3850X MDF stack with Mgmt Vlan1 (10.0.1.x).  In a remote building I have a 3750 switch (10.0.1.7) that I cannot ping or telnet to from my MDF.  The link between the two buildings is via an Engenius Bridge ENH202 using a Vlan5 address.  I've verified with their support that Vlan traffic is passed transparently, they suspect a VLAN mismatch somewhere in my network.  From my MDF stack, I am able to ping or telnet every other remote switch I have in Vlan1--the switch behing the bridge connection is the only one that will not respond.  HOWEVER, the client machines behind this switch are able to browse the entire network, communicating with every Vlan we have.  I cannot even ping or telnet to this switch from a client pc that is connected to this switch.  It makes no sense to me.  The client machines are on Vlan5, the phone is on Vlan10  and the door lock is on Vlan15.   Everything talks to each other except for Vlan1 on this specific switch.  I've tried to trace route to this switch from the Vlan5 pc that is directly connected and it times out.  When I first brought up this switch it worked intermittently but now it is unreachable.  I've even swapped out the physical switch with different hardware (same config), no change.  Attached is the config from the remote switch and the config from my MDF along with several show commands run on the remote switch.  If anyone has any thoughts, please chime in--I'm fresh out of ideas.  Thank you!

[johnd2310]

Hi,

"Gig 1/0/1          163         R S I     WS-C3850-4Gig 2/0/42"

Your cdp neighbor is show remote switch gi1/0/1 connected to 3850 port 2/0/42 but 2/0/42 is configured as follows:

interface GigabitEthernet2/0/42
switchport access vlan 5
switchport mode access
switchport voice vlan 10
no mdix auto
spanning-tree portfast

is this correct? should  remote switch not be connected to interface GigabitEthernet2/1/4

Thanks

John

[Deanna Wetzel]

Thank you for pointing that out.  I think somewhere along the line I tried configuring this port as a trunk and was unable to do so.  I then moved the bridge to an actual trunk port instead of trying to use a std port and was unable to get any connectivity to the remote building at all.  Before upgrading my MDF to 3850X the bridge was run through a standard port (on a 3750G), so perhaps I have to change something on that config if connected to a trunk....  I'll look into that tomorrow and see what I can work out.  Thanks again for noticing that--I've looked at it from so many angles that I couldn't see what was obvious.   I needed fresh eyes to take a look!  Thanks again so much.

[acampbell · Accepted solution]

Hi Deanna,

Look at your sh cdp nei table.

Remote-Kr#show cdp neighbor
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone

Device ID Local Intrfce Holdtme Capability Platform Port ID
<SNIP>
MDF3850X.abc.com
Gig 1/0/1 163 R S I WS-C3850-4Gig 2/0/42

Your 3750 is connected to interface gig2/0/42 on the MDF - this is a user port allowing only
vlans 5 & 10 NOT 1.

Either move to connection to another trunk port or rebuild gig2/0/42 as a trunk

Regards
Alex

[Deanna Wetzel]

Thank you for pointing that out.  I think somewhere along the line I tried configuring this port as a trunk and was unable to do so.  I then moved the bridge to an actual trunk port instead of trying to use a std port and was unable to get any connectivity to the remote building at all.  Before upgrading my MDF to 3850X the bridge was run through a standard port (on a 3750G), so perhaps I have to change something on that config if connected to a trunk....  I'll look into that tomorrow and see what I can work out.  Thanks again for noticing that--I've looked at it from so many angles that I couldn't see what was obvious.   I needed fresh eyes to take a look!  Thanks again so much.