cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
Announcements
Popup Hotspot Using ISR 1000 with WiFi/LTE for Teleworkers and Micro Branchesr
1119
Views
0
Helpful
7
Replies
Highlighted
Beginner

SG300-28P DHCP Lease expired / Not Renewing

Hi,

My SG300-28P was configured with DHCP and was working fine until the client leases expired. The client IP addresses were not renewed, or should i say the switch never re-issued an address.

The logs state that the DHCP Binding has expired.

I have to manually delete this binding for the IP address to be re-issued. Why is this happening?

Firmware v1.4.7 latest.

7 REPLIES 7
Highlighted
Beginner

Re: SG300-28P DHCP Lease expired / Not Renewing

Hello Adrian, you can reach out to the Cisco Small Business Support Center (SBSC), and one of the Cisco engineers will help you regarding this inquiry. Please visit the below link about the SBSC contact information.

 

https://www.cisco.com/c/en/us/support/web/tsd-cisco-small-business-support-center-contacts.html

 

Highlighted
Cisco Employee

Re: SG300-28P DHCP Lease expired / Not Renewing

Hi Adrian,

     I need to ask you a some questions please.

Where is your DHCP Server?

What mode is the switch in Layer 2 or Layer 3?

Are you using just DHCP Relay or Option 82?

Have you identified any DHCP relay interfaces?

Sorry for all the questions but it helps to understand the setup.

https://www.cisco.com/c/dam/en/us/td/docs/switches/lan/csbms/sf30x_sg30x/administration_guide/Cisco_300Sx_v1_4_AG.pdf

Max

P.S.

Reza is correct. They can jump in with you and look at it without all the Q&A back and forth.

Highlighted
Beginner

Re: SG300-28P DHCP Lease expired / Not Renewing

Hi Max,

Thanks for the response.

The DHCP server is configured an enabled on the switch.

No DHCP relay, Option 82 or relay interfaces.

The switch is in Layer 3 mode.

Highlighted
Cisco Employee

Re: SG300-28P DHCP Lease expired / Not Renewing

Adrian,

     Sorry for the delay in response. I reached out to some of my colleagues on the support side. There have been some issues related to DHCP for that model. There is truly no way to troubleshoot this through the forum. Please call in to open a case so they can work with you to get the necessary details to help you resolve. The number is 1-866-606-1866. They will open a case and start working with you to resolve. Have the serial number ready when you call in.

All the Best,

Max

Highlighted
Cisco Employee

Re: SG300-28P DHCP Lease expired / Not Renewing

Hi Adrian,

I tested basic scenario on SG300-28MP, hope this information can help you.
The expired ip address won't be re-issued if there are unused ip address in DHCP pool, but it will be re-issued if all ip addresses' state in the pool is expired.

Configuration:
ip dhcp pool network 100
address low 100.1.1.2 high 100.1.1.100 255.255.255.0
default-router 100.1.1.1
dns-server 8.8.8.8
exit

Refer to above dhcp pool, ip 100.1.1.2 is released by a PC, the ip address is marked as expired, and if a new PC access the network, 100.1.1.3 will be allocated to it. IP 100.1.1.2 won't be re-issued unless you delete the expired dhcp binding.
But if all addresses(100.1.1.2 - 100.1.1.100) is marked as expired, when a new PC access the network, 100.1.1.2 will be allocated to it.
So maybe the behavior is address allocation mechanism, not a issue, because the expired address can be re-issued if all addresses is expired in dhcp pool.

If you still have problems about it I will suggest you to open a case with CISCO TAC.

Yilin

Highlighted
Beginner

Re: SG300-28P DHCP Lease expired / Not Renewing

Hi Yin,

Thanks for this information. I will open a case as suggested. My concern is

whether the SG500 models have the same allocation mechanism.

Adrian.

Highlighted
Beginner

Re: SG300-28P DHCP Lease expired / Not Renewing

I have an SG300 28 ports and I face the same issue. The DHCP is full, expired bindings are not reused and the clients don't get IPs. BIOS version 1.4.8.6.

Any ideas?

CreatePlease to create content
Content for Community-Ad