Cisco 2960-S connected PCs not getting IP address until login

[serki.ashagre]

I’m having a strange thing going on. We recently bought Cisco 2960-S Series 48-Port Gigabit Power over Ethernet Switch to replace our old non Cisco switch. And I’m having network problems on computers that are connected to this switch. Currently have two switches (1 Cisco and 1 non Cisco connected to non-Cisco router).  

Problem:

I have noticed these on PC that are connected to the new Cisco switch.

1. When I try to boot from network (F12) to deploy OS I get “PXE exiting boot agent” error
2. After computer is turned on before user login, I have notice the network connection is limited with yellow exclamation mark on windows 8.1 login screen   
3. When some users login to their PC they get cant connect to server error often and they need to do refresh to get all mapped drives   

Things I have checked

I have used the other switch to point out the problem. I have connected a computer to the non cisco switch and check all the above things. I’m able to boot from F12 and the network connection is not limited on windows screen before login. But when I change the switch to the Cisco (Same OS, same NIC, Same cable, same faceplate, and same patch panel) I see all the things I above.

So I’m sure the problem is with the Cisco switch but I don’t know what.

Can anyone please help me?

Thanks,

Serki  

[Charles Hill]

Hello,

Are the ports configured with authentication?  Dot1x?

[serki.ashagre]

@Charles

We haven't made any custom configuration on the switch. We bought it and we put it in. no Port configuration is done.

Thanks  

[Charles Hill · Accepted solution]

Try entering the command below only on the ports that connect to pcs.

Interface gig x/x

spaaning-tree portfast 

[serki.ashagre]

Thanks for your suggestion. I entered the command on one port and it worked :) . so do I do the same with the other ports as well? will there be any disadvantage I should be aware?

Thanks   

[Charles Hill]

no disadvantage as long as it is applied to a port with an end device connected.

see document below for more info on portfast.

http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst4000/8-2glx/configuration/guide/stp_enha.html#wp1019884

Glad it's working for you!

please rate helpful posts.

thanks