How does a DHCP server automatically release IPs whose leases have expired?

1. First find out the IP address that is not currently being used, and use the ping command to see if the IP is used at this time.

2. Find out the physical address (MAC address) of the host that needs to be configured at present, which is required when the DHCP server excludes the address.

3. Log in to the DHCP server and open the DHCP management page.

4. Select the corresponding CIDR block and right-click in the reserved area.

5. Select New Reserved Area, fill in the description, IP address, and MAC address.

.This IP address will not be obtained by other hosts in the LAN.

First, find out the IP address that is not currently in use.

Then use the ping command to see if the IP address is used at this time.

2. Find out the physical address (MAC address) of the host that needs to be configured.

When the DHCP server.

This is required when excluding addresses.

3. Log in to the DHCP server and open the DHCP management page.

4. Select the corresponding CIDR block.

Then right-click on the reserved area.

5. Select the new reserved area and fill in the description, IP address and MAC address.

6. Other hosts in the LAN will not be able to obtain IP addresses.

After the client lease expires, it will automatically send a request to the DHCP server again to obtain the IP address, and then the DHCP server will give him an IP address again, and if you apply again, the IP address may or get the IP used last time, because DHCP seems to be randomly assigned an IP address, but if the client obtains the IP address from the DHCP server for the first time, the DHCP server will record the MAC and IP of the client at this time, if you apply again next time, And if this IP address is not separated, then this record will be used first. Then there's your problem, the lease will always be there, because it will be automatically renewed after it expires. The above is a personal opinion, thank you!

<>2, enter the password in the dialog box in the window.

3. Find the "LAN" setting on the left side of the router management interface and click to turn it on.

4. Finally, you can set the lease time in the "DHCP service" and solve the problem.

Legal analysis: The router DHCP lease time means: 1. If the lease time is exceeded, the IP address is released, but the list of IP addresses and MAC addresses has not been cleared.

But at this time, there is no new computer to apply for an IP address (there is no situation where the IP address is not enough). The original IP address will also be assigned to you. 2. If there are not enough IP addresses in the address pool, the IP addresses that expired before will be leased out.

That is, the contract expires.

Legal basis: Article 563 of the Civil Code of the People's Republic of China The parties may terminate the contract under any of the following circumstances:

1) The purpose of the contract cannot be achieved due to force majeure;

2) Before the expiration of the performance period, one of the parties clearly indicates or shows by its own conduct that it will not perform the main debt;

3) One of the parties delays the performance of the main debt and fails to perform it within a reasonable period of time after being reminded;

4) One of the parties delays the performance of its obligations or commits other breaches of contract, resulting in the inability to achieve the purpose of the contract;

5) Other circumstances provided for by law.

In the case of an indefinite contract with the content of a continuously performed debt, the parties may terminate the contract at any time, provided that they notify the other party before a reasonable period of time.

If you need a large number of addresses, in order to avoid insufficient addresses, you should set it short, if you set it long, it may lead to some people not being able to get the address and not be able to access the Internet. The lease term represents how long an address will be available to you, after which you will need to apply for a new address.

For example, if you have 100 bicycles, you can meet 100 bikes, but you can also meet 150 people, but you can only meet 100 people at the same time, maybe 75 people in the morning, 75 people in the afternoon, although there are only 100 bikes, but in fact they serve 150 people. The lease term represents how long you can use it. The default means that the default value is balanced.

If it is for home use, you can use it for your own family, you can turn off DHCP and set up IP binding to improve the stability of the router. Method: 8 home fixed IP devices, 6 DHCP address pools, 1 minute lease.

Home routers are all low-grade configurations, and the functions can't be opened too much, and the high-configuration local tyrants are by the way, and the right ones are the best.

How to set the router lease time is automatically assigned by the router, and the general default is 2 hours, which can be adjusted manually. The lease time refers to the time allowed by the host to occupy an IP address. If the occupancy period has expired, the contract will be automatically renewed.

Enter the router address, enter and password in your browser to log in to the router. Enter the home page of the Qiliang Approach Shenkuan Device, and select the DHCP server as shown in the figure to enter the configuration interface. Enable the DHCP server, specify the IP address allocation range of the DHCP server, the IP address leasing cycle, and do not need to fill in the other special needs, click Save.

Go to the "DHCP server" in the router and set the "DCHP service" setting option, and then there is an address lease period, just change it.

Log in to the router DHCP server -> DHCP service -> The address rental time is set in minutes, and you can supplement it to use it permanently, and disable the DHCP service! DHCP is a protocol for dynamic IP allocation. After disabling.

If you want unlimited time, there are two ways to do this: 1) configure a static IP address on your computer's network card; 2) Configure static address reservation in DHCP on the router calendar; If you think that the DHCP period is too short, it is recommended that you change the DHCP rental period to a maximum of 2880 minutes (2 days).

Yes, the default time of each router manufacturer is different at this time, and you can change it after entering the background page.

The DHCP server sets the Address Lease Term to be assigned to the IP configuration information used by the client, which is 8 days by default.

The IP configuration information obtained by the client can only be used for 8 days, and when the expiration date expires, the IP configuration information must be re-applied to the DHCP server, so the IP address of the client will be changed.

To put it simply, it is the period of time that can be used after obtaining the IP address, and if you have been using this IP all the time, then even if the lease period is reached, the IP will be obtained first when you automatically re-obtain.

For example, the ADSL dial-up Internet used by the home is to obtain the IP address through the DHCP server of the ISP, and each broadband dial-up Internet connection uses the DHCP protocol, and the IP address is assigned by the ISP (network operator), and the role of the "address lease term" here is to regularly change the IP address of the user.

"Lease Term" refers to the period of time during which the DHCP server allocates IP configuration information to the client for use, which is 8 days by default.

In other words, the IP configuration information obtained by the client can only be used for 8 days, and when the service period expires, the IP configuration information must be re-applied to the DHCP server, so the IP address of the client will change, which increases the difficulty of the NMS to manage the client.

To put it simply, it is the period of time you can use this IP address after you get it, if you have been using this IP all the time, then even if the lease period is reached, you will get this IP first when you automatically re-obtain, but when you have not used this IP for a long time, then the next time you get it will be another address.

The term of an IP address lease is the term of use of the IP address configuration information obtained by the client computer from the DHCP server. After the client automatically obtains an IP address, it will generally have a certain period of use, after which it needs to apply for a new IP address. However, frequent IP address changes can cause administrative problems, and users can set the IP address lease term to give the client computer permanent access to the IP address.

That is, after the client obtains the IP, within the lease, the client can get the same IP first, and then look for a new IP when it connects again

1.Click "Start Programs Management Tool DHCP" to open the DHCP console window.

2.Select the DHCP server name, right-click the server name, select New Scope from the shortcut menu that appears, click the Next button in the window that appears, enter the relevant information in the dialog box that appears, and click the Next button.

4.Enter the IP address range that you want to exclude. Since there are many network devices in the campus network that need to specify static IP addresses (i.e., fixed IP addresses), such as servers, switches, routers, etc., these assigned IP addresses must be excluded from the IP address range of the DHCP server, otherwise IP address conflicts will be caused and network failures will occur.

5.Click the [Next] button to set the time value of the IP address lease period in the "Lease Term" window that appears. In general, if the IP address in the campus network is tight, you can set the lease period shorter, and when the IP address is looser, you can set the lease period longer.

After the settings, click the [Next] button and the "Configure DHCP Options" window appears.

6.In the "Configure DHCP Options" window, if you select Yes, I want to configure these options now, you can set the DNS server, default gateway, WINS server address, etc. If you select No, I want to configure these options later, you can configure them when you need them. Here, we select the former, click the [Next] button.

7.In the window that appears, you often enter the IP address of the router (i.e., the IP address of the default gateway) or the IP address of the NAT server (Network Address Translation Server), such as WinRoute and Sygate. In this way, the IP information that the client gets from the DHCP server contains the default gateway settings, so that it can access the Internet.

8.Click the [Next] button to set the name of the client DNS domain in this dialog box, and enter the name and IP address of the DNS server. , and then click the [Add] button to confirm.

9.In the window that appears, select Yes, I want to activate this scope now, click the [Next] button, and click the [Finish] button in the window that appears, and the setting ends. At this point, you can see the scope we just created in the DHCP manager.

2. Enter the account password in the dialog box in the window.

3. Find the "LAN" setting on the left side of the router management interface and click to turn it on.

4. Finally, you can set the lease time in the "DHCP service" and solve the problem.

Go to the "DHCP server" in the router and set the "DCHP service" setting option, and then there is an address lease period, just change it.

It should be that your DHCP server is too burdensome, the shorter the lease period, the more clients, the more information the DHCP server will process, and if the performance is poor, it may cause the failure you said.

Address release: It means that the client obtains an IP address and uses it, and the server side also assigns this IP address to him to use, but the server side sets a lease period, and the IP address will be ** after the lease period, and the next time the client wants to obtain the IP address, it will re-apply, and the application will be screened from the address pool, of course, it is possible to apply for the same IP address as last time.

2. Release the IP address.

If you want to release the IP address, you can run the command ipconfig renew on the client side (this should be the case if memory serves).

Hope it helps. Thank you!