Problem Description : AP2750 does not bootup after some operational time / Could not access wireless network / Could not see AP2750 on line

• AP 2750 constantly reboots
• Product Model # : 3CRWX220095A - 3Com® Wireless LAN Controller WX2200
• 3CRWX120695A - Com® Wireless LAN Switch WX1200
• 3CRWXR10095A - 3Com® WXR100 Remote Office Wireless LAN Switch
• 3CWXM10A - 3Com® Wireless Switch Manager
• 3CRWX440095A - 3Com® Wireless LAN Controller WX4400
• 3CRWX275075A - 3Com® Wireless LAN Managed Access Point 2750
• Software / Firmware version : V7 MSS and 3WXM
• Fact : APs are distributed in the layer 3 network environment
• DHCP server available to assign IP address to AP
• Static IP address configured to AP 2750
• Recent Changes : None

Cause : When an AP has static ip address configured via the WX, the WX refuses AP to boot from other ip address In this case, the AP2750 somehow obtains an ip address during the bootup process and use this ip address to contact WX - WX refuses to boot this AP up.

Here is the AP 9935 configuration on WX:

#
set ap 9935 serial-id l9dq74j1fa680 model AP2750  
set ap 9935 name AP13
set ap 9935 fingerprint 1f:67:2b:fc:76:6a:39:a6:25:8e:8c:3d:25:53:fb:80
set ap 9935 radio 1 mode enable tx-power 13 
# 

Here is the static ip configuration of AP 9935:

# 
disp ap boot all 
Static Boot Configuration 
AP: 9935 
IP Address:  Enabled
VLAN Tag:    Disabled
Switch:      Enabled 
Mesh:        Disabled 
IP Address:      10.60.64.94
Netmask:       255.255.248.0
Gateway:         10.60.64.94 <<<<<<<<<<< not correct
VLAN Tag:                   
Switch IP:       10.60.64.94 <<<<<<<<<<<< not correct
Switch Name:                
DNS IP:                     
Mesh SSID:                  
Mesh PSK:    
# 

Here is the log trace of AP9935 showing that AP 9935 uses ip address of 10.60.65.212:

# 
APM_FMX Jul  1 11:09:20.658481 DEBUG dap_pak_input: inpport=1 smac=00:18:6e:1f:a
6:80 dmac=ff:ff:ff:ff:ff:ff src=10.60.65.212 dst=10.60.71.255
APM_FMX Jul  1 11:09:20.658490 DEBUG dap_pak_input: type=request len=68 flags=9 
snum=L9DQ74J1FA680
APM_FMX Jul  1 11:09:20.658835 NOTICE AP_NOTIFY: SW-find request from AP serial_
id l9dq74j1fa680 mac 00:18:6e:1f:a6:80 port 1 vlan default succeeded with IP-add
ress 10.60.64.74 flags 25 bias 1 sec 1  
# 

Fix : Two actions required:

- Reconfigure the static ip address to have correct WX ip address on AP. 
- On the DHCP server reserve the ip address assigned to AP2750 to the MAC address of AP 2750 - when AP2750 requests an ip address from DHCP server, server always assigns fixed ip address to each AP 2750 

— David Gonzalez 2021/03/30 14:58