The importance of DHCP's allocation of lease term

In the past, it has always been the default lease term, and we should have never encountered the problem of Internet access in some places and Internet access in some places. Today, I encountered the problem of access to the Internet downstairs and upstairs. I will describe and record the incident below, and give you a way to solve the problem:

1. problem

In the morning, someone reported that the WIFI upstairs could not be connected to the Internet, but could not get the IP address.

two。 Cause of the problem

It is suspected that it may be a line problem, but after plugging the wireless cable directly into the PC to get the address, I still can't get the address, so I looked for the reason of the next level of equipment. First, I connected the network cable directly to the switch to see if I could get the IP address, and finally failed (because we have a firewall, there are only three ports and a WLAN,2 LAN, all of which have been used, so I don't connect directly to the firewall) In the end, the problem fell on the firewall. I thought that PC could not get the IP address, so I went to the DHCP address pool. Sure enough, the address pool was full, but why was it full and there were not so many PC ends? So I checked the settings of the DHCP server and found that the lease term of the DHCP address pool was set to "indefinite".

3. Problem summary

Don't ignore small settings, it may bring inconvenience to your work!