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Strange Connectivity Issue

dcanady55
Level 1
Level 1

Hello,

I cannot ping a switch that sits on the same vlan/subnet as me from my laptop. The switch is up and active and I can ping it from other machines here on the LAN. I have tried the following from on my laptop: plugged into another port, rebooted, cleared my ARP, tried adding a static ARP entry with mac and IP. When I capture with Wireshark I can ping my gateway and see the ICMP logs but when I ping this switch there are no ICMP logs in WS. When I ping the address it returns reply from x.x.x.x address which is my laptop and error "destination host unreachable". I can ping and SSH into any other networking devices across the LAN and WAN. When I look in WS I can see the ARP request being sent out to my broadcast address but nothing after the initial request. 

 

Thanks,

9 Replies 9

Jon Marshall
Hall of Fame
Hall of Fame

You are sure that -

1) you are using the same subnet mask on both the switch and laptop

2) the port your laptop is in the right vlan

3) there are no acls that could be blocking your traffic

Jon

Positive. There are no ACL's setup on that switch or the core switch which is my default gateway. From the core switch I pinged both my laptop and the other switch and both are in the same vlan. I vnc into a server on the same subent/vlan and installed Putty and ssh into the switch. From the switch I also could not ping my laptops IP but could ping other addresses on the LAN. 

Is there a firewall on your laptop ?

It shouldn't stop you pinging out to be honest but if every other device can get to and from the switch it sounds like an issue with the specific laptop.

On the switch does it see the laptops mac address ?

Jon

 I have windows 7 and FW is not enabled. When your asking if the switch sees the laptops mac are you referring to the switch I cannot ping or the core switch? The core can see my laptops mac just fine and the mac of the switch I cannot ping. The other switch cannot see my laptops mac. 

The switch your laptop is connected to.

Are there other machines in the same vlan connected to that's switch.

If so can -

1) those machines ping that switch (not the core switch)

and

2) can you ping those other machines

Jon

Jon,

to give you a better overview. My laptop is connected to a user switch which is connected tot he core. The switch I cannot ping is connected directly to the core. However, to answer your other questions yes those other machines that can ping the switch are also tied to the user switch and on the same vlan and yes I can ping them. This is a very strange issue. 

It is strange to say the least.

The switch is obviously not receiving your arp request but it obviously should do if it is all in the same vlan.

If there are no acls within the vlan and your laptop and the switch are using the same subnet mask then its difficult to understand where your broadcast is getting lost.

Jon

when I figure it out I will let you know. I was able to get on the wireless vnc and ping the switch so it's related to my LAN NIC somehow. 

More food for thought. I put an IP phone which granted sits on a different subnet but it's working off the switch I cannot ping, I successfully was able to ping the IP address of this phone. 

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