I cannot ping Cisco 3850 during working via external Wi-Fi

[elsayedm1]

Hello Dear's

I faced issue regarding ping to the core switch when I connect the Wi-Fi such Mobile Wi-fi, in that time I cannot reach any VLANs in the core switch ( cisco 3850) 

 Cisco ONE Discussions

are here any person faced the same issue?

[Francesco Molino]

Hi

Can you give more details on your architecture?
Is your wifi vlan hosted on the same core switch? In a dedicated vrf? Or behind a firewall?

[elsayedm1]

Hi Francesco, 

thanks for your fast replay, 

please find attached scenario, it will help you to understand what the issue exactly.

[Francesco Molino]

In your diagram, we don't see how the wifi AP is connected to your 3850 switch.

If no connection exists between your wifi and switch (layer 2 or layer 3 through a router), you won't be able to access any vlans when connected over wifi.

Can you detail your connectivity between wired and wifi?

[elsayedm1]

Hi Francesco, 

actually there no VLAN for wifi, I used both network cards in my laptop, one connected to Switch 3850 and another card (wireless Card) connected to Personal wifi. 

once I connect to Personal wifi I cannot reach any server in the network.

[paul driver]

Hello

---

@elsayedm1 wrote:

Hi Francesco, 

actually there no VLAN for wifi, I used both network cards in my laptop, one connected to Switch 3850 and another card (wireless Card) connected to Personal wifi. 

once I connect to Personal wifi I cannot reach any server in the network.

---

So the question is what is your laptop connecting to via its WiFi card - As it isn’t connecting to the switch it needs to connect to some sort of WiFi access point and if that WiFi access point isn’t connected to the switch and it’s vlans not so sure how do you expect it to work?

[Andrew Khalil]

Hello Paul,

His PC is connected to 2 different networks, 1 to the switch "wired" and 1 to the access point "wireless", so his PC has 2 NIC.

As I understood (because it is a common issue) he was able to ping the switch when he was only connected through the ethernet NIC, once he connected his PC to the AP, he lost pinging! 

Such an issue happens due to the metric of the wireless connection could be lower than other wired connection,

I recommend to use a sourced pinging through the command:

ping x.x.x.x -S y.y.y.y

where x.x.x.x is the sw ip address while the y.y.y.y is the ethernet NIC ip address.

he can also check the command:

route print 

to know the metrics of the different routes!

I guess this is the problem, according to my understanding! 

I hope it will be helpful enough to get the rating ))) 

Bst Rgds, 

Andrew Khalil

[Richard Burts]

I agree that the output of route print and perhaps of ipconfig might be helpful. It sounds to me that the routes learned from wifi are taking precedence and that those routes do not have entries for the subnets/vlans connected to his switch.

HTH

Rick

[Georg Pauwen]

Hello,

what brand/model is your workstation ? With some models (I know Dell laptops have this) you cannot connect both WiFi and Ethernet at the same time unless you change the BIOS settings...

[elsayedm1]

Hi Georg

thanks for your replay.

we have HP & TOSHIBA laptop.

[Georg Pauwen]

You use both HP and Toshiba, and the same problem occurs on both laptops ? Which exact models do you have (e.g. 
HP Gaming Pavilion 15-cx0630nd) ? And are you running Windows 10 ?

[Georg Pauwen]

Hello,

on the HP, there should be a setting in the BIOS called LAN/WLAN Switching, which is enabled by default.

In order to get the WiFi and Ethernet working at the same time, go into the BIOS, find and disable the LAN/WLAN switching setting, save the change and exit the BIOS.

[elsayedm1]

Hi Georg,

Thanks for your replay,

let me apply this setting and I will update you.

[Andrew Khalil]

Hello Elsayedm1,

Greetings,

I would recommend not to type:

"ping x.x.x.x" in your Command line,

in stead you should type:

"ping x.x.x.x -S y.y.y.y"

keeping in mind that x.x.x.x is your switch IP address while y.y.y.y is your LAN NIC IP address.

And it will work!

Please test it and let me know the result to explain why you have this problem!

Also don't forget to rate my post if you have find it helpful!

Thanks and best regards,

Andrew Khalil

[Andrew Khalil · Accepted solution]

Hello elsayedm1,

Happy to provide for you a helpful reply, please if it helped you to solve your problem, mark it as a soultion! 

It will so nice from you!

Bst Rgds,

Andrew Khalil