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mbj
Beginner
Beginner

Wacky Routing issue with VLAN

I have a 3825 router that I have setup with the following:

interface GigabitEthernet0/0

no ip address

ip flow ingress

ip flow egress

duplex auto

speed auto

media-type rj45

negotiation auto

no mop enabled

service-policy output MARK-PCOM-VIDEO

end

interface GigabitEthernet0/0.1

description Baraboo, WI LAN$ETH-LAN$

encapsulation dot1Q 1 native

ip address 10.22.10.7 255.255.0.0

ip helper-address 10.22.10.241

no snmp trap link-status

end

interface GigabitEthernet0/0.172

description Baraboo VLAN 172

encapsulation dot1Q 172

ip address 172.22.1.1 255.255.255.0

no snmp trap link-status

end

Its on a trunked port to my 3750 switch. I am new to this compnay and havent changed it over to IP routing on the switch quite yet.

Both Vlans are setup on the 3750 without an SVI. All hosts on VLAN 1 can ping both interfaces without issue.

If I put a host on the 172 VLAN it cannot ping anything on the router. If I put another host on the VLAN they can ping each other. If I put an SVI on switch the 172 VLAN hosts can ping the switch, but still not the router. ONce I put the SVI on the switch, it can no longer ping the  router. I am giving the SVI ip 172.22.1.5/24.

I have verfied with TAC that the trunk is allowing the vlans to the router.

I have been working with TAC. They have asked me to update the code on the switch, but I think they are just punting.

Swith is running:

c3750e-universalk9-mz.122-58.SE2

TAC wants me to go to c3750e-universalk9-tar.122-55.SE5.tar:

Router is running:

c3825-advsecurityk9-mz.124-3i.bin

thoughts?

Also this is my first time posting, so if I left out some info let me know.

23 REPLIES 23

  On the switchport on the 3560 on g1/0/23  try adding "switchport nonegotiate"  and report back .  It's possible that because the 3750 is a vtp server and is in a different vtp domain or no domain in the  router case  it may keep the trunk from coming up correctly .  This is the problem with hardcoding trunks as long as you have a physical link it will tell you it's trunking when it might not be .  Going to a router you have no choice but to hardcode so there is really no way around that. If this doesnt work I'm out of ideas . 

Hi, would it be possible for u to post the show run & show ip route, sh ip arp from the router and show spanning-tree vlan 172 from the switch. Also when u have a host in vlan 172 and when u try to ping the router ip do u see outbound pkts incrementing on g1/0/23. Thx

One more thing Is it possible that any of your hosts might have the same ip as your router. Can u confirm if the mac entry on your host matches the mac of the router.

Thx

Added switchport nonnegotiate, no luck.

Aileron88
Beginner

So in summary, you're only having issues with tagged frames over a trunk.

Can you please issue a 'show interface g1/0/23 switchport' on the 3750 and a 'sh int g0/0' on the 3825.

Thanks,

Adam

Sho INT GIG0/0

MSA3800#sho int gig0/0

GigabitEthernet0/0 is up, line protocol is up

  Hardware is BCM1125 Internal MAC, address is 0023.0470.a2d0 (bia 0023.0470.a2d0)

  MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,

     reliability 255/255, txload 1/255, rxload 1/255

  Encapsulation ARPA, loopback not set

  Keepalive set (10 sec)

  Full-duplex, 1000Mb/s, media type is RJ45

  output flow-control is XON, input flow-control is XON

  ARP type: ARPA, ARP Timeout 04:00:00

  Last input 00:00:00, output 00:00:00, output hang never

  Last clearing of "show interface" counters never

  Input queue: 0/75/693/2 (size/max/drops/flushes); Total output drops: 155

  Queueing strategy: Class-based queueing

  Output queue: 0/1000/64/0 (size/max total/threshold/drops)

     Conversations  0/23/256 (active/max active/max total)

     Reserved Conversations 1/1 (allocated/max allocated)

     Available Bandwidth 250000 kilobits/sec

  5 minute input rate 6033000 bits/sec, 752 packets/sec

  5 minute output rate 2431000 bits/sec, 623 packets/sec

     782071494 packets input, 2240142197 bytes, 0 no buffer

     Received 8562996 broadcasts, 0 runts, 0 giants, 31 throttles

     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored

     0 watchdog, 2248415 multicast, 0 pause input

     0 input packets with dribble condition detected

     733199563 packets output, 2585060426 bytes, 0 underruns

     9 output errors, 0 collisions, 6 interface resets

     0 babbles, 0 late collision, 0 deferred

     9 lost carrier, 0 no carrier, 0 pause output

     0 output buffer failures, 0 output buffers swapped out

Cisco3750-a#sho int gig1/0/23

GigabitEthernet1/0/23 is up, line protocol is up (connected)

  Hardware is Gigabit Ethernet, address is 0022.bda2.b717 (bia 0022.bda2.b717)

  MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec,

     reliability 255/255, txload 2/255, rxload 1/255

  Encapsulation ARPA, loopback not set

  Keepalive set (10 sec)

  Full-duplex, 1000Mb/s, media type is 10/100/1000BaseTX

  input flow-control is off, output flow-control is unsupported

  ARP type: ARPA, ARP Timeout 04:00:00

  Last input 00:00:00, output 00:00:00, output hang never

  Last clearing of "show interface" counters never

  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 19

  Queueing strategy: fifo

  Output queue: 0/40 (size/max)

  5 minute input rate 2931000 bits/sec, 879 packets/sec

  5 minute output rate 10467000 bits/sec, 1156 packets/sec

     159496831 packets input, 60740883950 bytes, 0 no buffer

     Received 750524 broadcasts (427195 multicasts)

     0 runts, 0 giants, 0 throttles

     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored

     0 watchdog, 427195 multicast, 0 pause input

     0 input packets with dribble condition detected

     211681195 packets output, 200393435881 bytes, 0 underruns

     0 output errors, 0 collisions, 1 interface resets

     0 unknown protocol drops

     0 babbles, 0 late collision, 0 deferred

     0 lost carrier, 0 no carrier, 0 pause output

     0 output buffer failures, 0 output buffers swapped out

mcollaery
Beginner

Just one little thing - use the button on the front of your stack of 3750s to confirm how they are numbered in their stack 1, 2, 3.

Maybe G1/0/23 isn't actually the port you think it is.

mbj
Beginner
Beginner

So I did some layer 1 troubleshooting.....

I of course assumed that logically the Router was plugged directly into our core switch....oops. It turns out the last network engineer plugged the router into a Netgear switch that plugged into the router.

So after fixing this issue...it has been resolved. Wow I cannot believe I didnt look at the wiring.

Richard Burts
Hall of Fame Guru

Aaron

Thanks for posting back with the update. I am very glad that you have solved the issue and have shared the solution with us.

If anyone needs it, this is a very good reminder that in troubleshooting what might appear to be a layer 3 routing problem that we need to be very careful to verify layers 1 and 2.

Now perhaps you can mark this question as answered?

HTH

Rick

HTH

Rick

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