Hi All
This is driving me mad at the moment and it should be very easy!
I've got 3 switches (Cisco Catalyst 3750 with ADVIPSERVICESK):
3750-HQ1 with 3750-HQ2 and 3750-3 connected to it via dot1q trunk ports.
On 3750-HQ1 I have an interface called VLAN99 with IP address 10.0.0.241
On 3750-HQ2 I have an interface called VLAN99 with IP address 10.0.0.242
On 3750-3 I have an interface called VLAN99 with IP address 10.0.0.243
I can ping 10.0.0.242 from 3750-HQ1 and vice versa, but we cannot get any pings from/to 3750-3 on VLAN99.
Please have a look at the three config files attached and see if there's anything blindingly obvious that I'm obviously too blind to see?
I've been banging my head against this all day!
Thanks!
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Try logging into all the switches and check the output using
show interfaces trunk
With this output you shall know how many trunk links are formed between switches.
From the text files you attached, I observed that there wasnt any trunk link specified from hq 2 to switch 3750-3
You might have to configure a trunk .between hq 2 and switch 3750-3.
That should take care of it.
Hi guys
Thanks for the comments. I'll be able to run a few commands on Tuesday. In the meantime, some more info. I'm also fairly certain (from memory) that VLAN 99 does exist on HQ3 - but I'll confirm on Tuesday.
I should have explained a bit better how these switches are connected. Imagine HQ1 as the "core" switch. HQ2 is hanging off port 1/0/24 and HQ3 is hanging of port 1/0/10. There is no direct link between HQ2 and HQ3.
On HQ1:
Port 1/0/10:
interface GigabitEthernet1/0/10
description xxxxx connection to xxxx 90Mbps Max
switchport trunk encapsulation dot1q
switchport mode trunk
speed 100
duplex full
Port 1/0/24:
interface GigabitEthernet1/0/24
description Downlink to CAT-3750-HQ2
switchport trunk encapsulation dot1q
switchport mode trunk
duplex full
Also what I didnt mention is that I can successfully ping on VLAN99 bwteen HQ1 and HQ2 - it's just 3 that's not working as it should.
Thanks
TB
OK, I've change VLAN 99 interface IP address on switch 3 to 10.0.0.175 in case there was a conflict. This didn't fix it. I've then done a "clear arp" on all the switches and then did a "show arp | incl 10.0".
On Switch 1 and 2 it's all fine (I see entries from each of these on each other), but on Switch 3 there's some wierdness. Look at the mac address for 10.0.0.1 - can this point to something else that's wrong?
Thanks
If you have a free port on both switches set them up a mirror ports and run a packet capture to verify that each switch is putting VLAN 99 traffic outbound on the appropriate interface.
Oh, the incomplete on the arp entry for 10.0.0.1 just means that it sent out the arp request and it never got a response. Which is just another indication that something weird is going on with VLAN 99.
Um, well we had a similar issue a couple of weeks ago with a 4507. End the end we configured the trunk port to all all VLAN's, then changed it back to just limiting the VLANs we wanted and then all of sudden it started to work.
So on CAT-3750-3 you may want to change interface GigabitEthernet1/0/13 to that it allows all VLAN's. Check and see if the pings start to flow, then go back and only allow the VLANs you want.
Hi guys (admins included)
I need to put this on hold, but I don't want to close the issue. Problem is I cannot really modify the config of this switch (specifically port 1/0/13) at the moment as it is critical not to have any downtime at the moment.
Can we just leave this call open or should it be put "on hold" in some way? I don't want to cancel it since someone could still come up with a simple solution while waiting for me to get a window for testing.
And the points are still up for grabs.
Cheers
TB
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by: donjohnstonPosted on 2009-05-01 at 12:17:03ID: 24282595
I'm guessing that you don't have a trunk port on HQ2 going to HQ3. I can't say for sure since you don't specify which ports are used to connect HQ2 to HQ3.