Configuring a DHCP Server

You can configure a DHCP server to assign IP addresses to APs and STAs.

A service DHCP address pool and a management DHCP address pool are used to assign IP addresses to STAs and APs, respectively. The two types of DHCP address pools must be configured separately.

Configuring a DHCP Server

To go online successfully, APs and STAs must obtain IP addresses. You can configure an AC as a DHCP server or use an independent DHCP server to assign IP addresses to APs and STAs.

You cannot configure a STA associated with an AP as a DHCP server.

When an enterprise branch has no independent DHCP server, configure an AC as a DHCP server.
An independent DHCP server applies to WLANs in medium- to large-sized campuses.

Depending on different devices functioning as a DHCP server, the configuration is as follows:

For details about how to configure an AC as a DHCP server, see Configuring a DHCP Server in Configuration Guide - IP Service.
For details about how to configure an independent DHCP server, see related product configuration manuals.

When the AC and APs are on the same network segment, the APs can discover the AC in broadcast mode. You do not need to configure Option 43 or DNS. If either of the two methods is configured to notify the APs of the AC's IP address, the APs will preferentially send unicast Discovery Request packets to this IP address. If the APs do not receive any Discovery Response packet after sending the unicast packets 10 consecutive times, the APs broadcast packets on the local network segment to discover an AC.

If the AC and APs are on different network segments, you must configure Option 43 or DNS to specify the AC's CAPWAP source IP address for the APs. Otherwise, the APs cannot discover the AC and go online successfully.

Configuring Option 43

If an AC functions as a DHCP server to assign IP addresses to APs, perform the following operations:
1. Run the system-view command to enter the system view.
2. Run the ip pool ip-pool-name command to create a global address pool and enter its view.
3. Run any of the following commands to configure the option 43 field.
  - Run the option 43 hex 031D3139322e3136382e3139342e35302c3139322e3136382e3139342e3534 command to configure the device to specify the AC IP addresses 192.168.194.50 and 192.168.194.54 for APs. In this command, 03 is a fixed value; 1D indicates that the length of IP addresses (192.168.194.50,192.168.194.54) including dots (.) and the comma (,) is 29, and multiple IP addresses are separated by the comma (,); 3139322e3136382e3139342e3530 indicates the ASCII value of 192.168.194.50; 2C indicates the ASCII value of the comma (,); 3139322e3136382e3139342e3534 indicates the ASCII value of 192.168.194.54.
  - Run the option 43 sub-option 1 hex C0A80001C0A80002 command to configure the device to specify the AC IP addresses 192.168.0.1 and 192.168.0.2 for APs. In the command, C0A80001 indicates the hexadecimal format of 192.168.0.1, and C0A80002 indicates the hexadecimal format of 192.168.0.2.
  - Run the option 43 sub-option 2 ip-address 192.168.0.1 192.168.0.2 command to configure the device to specify the AC IP addresses 192.168.0.1 and 192.168.0.2 for APs.
  - Run the option 43 sub-option 3 ascii 192.168.0.1,192.168.0.2 command to configure the device to specify the AC IP addresses 192.168.0.1 and 192.168.0.2 for APs.
Run any of the following commands to configure the option 43 field. If multiple commands are executed on an AP in V200R006, only the last command takes effect. If multiple commands are executed on an AP in V200R007C10 or a later version, all the commands take effect.
option 43 sub-option 3 ascii ascii-string
option 43 sub-option 2 ip-address ip-address &<1-8>
option 43 sub-option 1 hex hex-string
If an independent DHCP server is used to assign IP addresses to APs, you must configure option 43. Otherwise, the APs cannot discover the AC and go online successfully. For details about the configuration, see related product configuration manuals.

Configuring DNS

In this mode, you need to configure the domain name and address of the AC on the DNS server.

If an AC functions as a DHCP server to assign IP addresses to APs, perform the following operations:
1. Run the system-view command to enter the system view.
2. Run the ip pool ip-pool-name command to create a global address pool and enter its view.
3. Run the gateway-list ip-address &<1-8> command to configure a gateway address for DHCP clients.
4. Run the network ip-address [ mask { mask | mask-length } ] command to set a network segment of the global address pool.
5. Run the dns-list ip-address &<1-8> command to configure a DNS server address for DHCP clients.
6. Run the domain-name domain-name to configure a domain name suffix for APs. After obtaining the suffix, the APs concatenate the suffix and huawei-wlan-controller into a fully qualified domain name (FQDN). The APs then use this FQDN to request the AC's IP address from the DNS server.
If an independent DHCP server is used to assign IP addresses to APs, you must configure the domain name suffix for APs. Otherwise, the APs cannot discover the AC and go online successfully. For details about how to configure an independent DHCP server, see related product configuration manuals.