Need help to find the location of DHCP logs in a Cisco l3 switch

[SUjith_k10]

Hello,

      I have configured multiple VLANs in a Cisco Catalyst 3750. This L3 switch is also acting as the DHCP source. I would like to know where can I find the DHCP logs in a this Cisco catalyst L3 switch? So I can direct it to a server where I can store the DHCP logs and manage it.

[johnd2310]

Hi 

What do you mean by DHCP logs? You can configure a DHCP agent to store the  bindings. 

Thanks

John

[SUjith_k10]

In pfsense firewall System Logs on the DHCP Tab, displays messages and events from the DHCP Daemon and the DHCP client for WANs.Each DHCP request and reply from DHCP clients is shown here, along with events and errors. IP addresses, MAC addresses, and client-supplied hostnames are all visible in the logs. Similar to that do we get the logs which shows the DHCP request and reply form the DHCP clients in a Cisco Catalyst 3750 L3 switch, When the switch is acting as the DHCP source? If not then, Is there any tool that can be installed for this purpose?

[johnd2310]

Hi,

DHCP on 3750 is not as fully fledged as DHCP on your pfsense. The DHCP on 3750 is limited.If you want to see requests and replies you can enable debugging but this might impact your switch. The 3750 can store leases to an external file via ftp or tftp. You cannot install any tools on the switch but you can monitor DHCP via snmp. I think you are better off keeping the DHCP on the pfsense firewall or getting a server to do DHCP. Have a look at following doc onj configuring IOS DHCP

http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipaddr_dhcp/configuration/12-2sx/dhcp-12-2sx-book/config-dhcp-server.pdf

Thanks

John

[SUjith_k10]

Hi,

 Thank you for your detailed explaination. Here if it is just the DHCP I can switch to pfsense in no time. But the main issue here is the number of VLANs configured. More than 20 VLANS are configured in the L3 switch. I think I will have to find a way to create VLANs in the pfsense and integrate that to the switch. Also the DHCP lease gets overwritten time to time even if that is exported via ftp to a remote system.

[Ganesh Hariharan]

Hi,

check out the below link hope that answers your query.

http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3750/software/release/12-2_58_se/configuration/guide/3750scg/swlog.html

-GI

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