I configured an DHCP server on cisco 3750 switch . Wher in w3750 gets connected to plain l2 switch 2960 on floor and machine gets connected to 2960 port.
w3750 -----trunk------w2960---- Machine
DCHP Configuration on core switch
ip dhcp pool IT
origin file flash1:dhcp-it.txt
dns-server 172.16.5.2 172.16.5.26
Below is the description of problem:
-> The Cisco 3750 switch is the DHCP server. VLAN 108 is named as internet vlan.
-> Ports in Cisco 2960 switch has been configured with "switchport access vlan 108".
-> There were no problems at all and everything had been working smoothly.
-> 3 days back, users started complaining that they couldn't access the internet. Up on troubleshooting the issue, I found out that there was an issue with the DHCP server as the computer couldn't get any IP address at all. After setting static IP address, the internet started working again.
If I bind IP to MAc address reservation on core 3750 switch for some time of moment it works but after that machine gets unreachable .
I restarted the 3750 switch and also all the 2960 switches over the weekend, however, the issue still hasn't been resolved yet. I did issue the command "clear ip dhcp conflict *", clear ip dhcp binding * but no joy at all.
I am stuck here and running out of ideas now. Can someone please help me out with this issue?
Please let me know if you want to have a look into the config/show command outputs.
is make sure its enabled.on all swithes that habe hosts attached and all swich intecomnects are trusted
have you ran out of ip addresses? how.long is your dhcp lease time?
have you tried removing the origin file amd manually specifying a ip range?
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