02-09-2023 03:48 AM - edited 02-09-2023 04:22 AM
hello,
I am a small home office user. Recently moved config from an old Cisco 1900 to a newer Cisco 1100 series.
I am unable to remove a excluded DHCP scope statement. From the cli "no ip dhcp excluded-address x.x.x.x x.x.x.x" does not remove the entry. As a result, I only have 25 DHCP addresses to play with, and the next DHCP clients are not being issued DHCP addresses. Pool is exhausted.
Ios config clearly has a DHCP exclusion scope... I have no idea how it got there but I can't remove it.
How can I remove the excluded-address statement please?
!
ip host CISCO-CAPWAP-CONTROLLER.local 10.0.2.5
ip host cisco-lwapp-controller.local 10.0.2.5
ip name-server 8.8.8.8 8.8.4.4
no ip domain lookup
ip domain name .local
ip dhcp excluded-address 10.0.1.26 10.0.1.255
!
I've tried deleting the DHCP pool, then removing the excluded-address entry, and then re-adding the DHCP pool. Issuing the command under config t does not remove the entry. A reboot does not remove the entry. it's like it's locked or read only or something.
no ip dhcp excluded-address 10.0.1.26 10.0.1.255
DHCP Debug log shows
DHCPD: subnet [10.0.1.1,10.0.1.254] in address pool LAN-pool1 is empty.
DHCPD: due to: POOL EXHAUSTED
Router address is 10.0.1.254
DHCP Pool assigned as
ip dhcp pool LAN-pool1
import all
network 10.0.1.0 255.255.255.0
default-router 10.0.1.254
dns-server 10.0.1.254
domain-name .local
option 43 ascii "10.0.2.5"
lease 1
DHCP utilisation shows
Pool LAN-pool1 :
Utilization mark (high/low) : 100 / 0
Subnet size (first/next) : 0 / 0
Total addresses : 65534
Leased addresses : 0
Excluded addresses : 245
Pending event : none
1 subnet is currently in the pool :
Current index IP address range Leased/Excluded/Total
10.0.0.1 10.0.0.1 - 10.0.255.254 0 / 245 / 65534
Clients connect via a catalyst switch via VLAN10 with DHCP helper address pointing to router.
interface Vlan10
ip address 10.0.1.97 255.255.255.0
ip helper-address 10.0.1.254
no ip redirects
no ip unreachables
no ip proxy-arp
ip pim sparse-dense-mode
ip igmp join-group 239.20.226.197
ip igmp version 3
ip cgmp
installed ios version
System image file is "flash:c1100-universalk9.17.08.01a.SPA.bin"
Cisco IOS XE Software, Version 17.08.01a
Solved! Go to Solution.
02-10-2023 03:45 AM
I found the problem.
There was this entry in the ios config
app-hosting appid guestshell
app-vnic management guest-interface 0
guest-ipaddress 10.0.1.254 netmask 255.255.255.0
end
I dont use the "app-hosting" capability on the Cisco 1100 router...and it appears to be bad news for DHCP scopes. Maybe carves out a chunk of address range for it's self? I dont know.
But as soon as I removed with
C1121X-8PLTEP(config)#no app-hosting appid guestshell
I got my DHCP pool back, and the DHCP exclusion had disappeared.
02-09-2023 06:06 AM
Hello,
try and disable the DHCP service first before removing the reservation:
1100(config)#no service dhcp
02-09-2023 04:17 PM - edited 02-10-2023 02:06 AM
Thanks Georg,
I tried disabling/removing the DHCP service and then removing the excluded address-statement, and it is still not removed. It is like it's administratively locked or read only. I get no message on console or log when trying to remove it.
The process I used described below;
Remove DHCP service
C1121X-8PLTEP(config)#no service dhcp
Remove DHCP pool
C1121X-8PLTEP(config)#no ip dhcp pool LAN-pool1
Save config
C1121X-8PLTEP#write mem
Remove exclude-address scope
C1121X-8PLTEP(config)#no ip dhcp excluded-address 10.0.1.26 10.0.1.255
Save config
C1121X-8PLTEP#write mem
show run and the exclude scope is still there
show run
C1121X-8PLTEP#ip dhcp excluded-address 10.0.1.26 10.0.1.255 <<< entry still there
Save and reload the router
C1121X-8PLTEP#copy run start
C1121X-8PLTEP#reload
after reload, the entry is still there
show run
C1121X-8PLTEP#ip dhcp excluded-address 10.0.1.26 10.0.1.255 << entry still there after reload
Try removing the exclude scope again
C1121X-8PLTEP(config)#no ip dhcp excluded-address 10.0.1.26 10.0.1.255
Save config
C1121X-8PLTEP#write mem
show run to see if the exclude scope is still there... and it's still there
show run
C1121X-8PLTEP#ip dhcp excluded-address 10.0.1.26 10.0.1.255
very frustrating.
I also tried viewing, then clearing DHCP conflicts. there was one record in there.
C1121X-8PLTEP#show ip dhcp conflict
IP address Detection method Detection time VRF
10.0.1.6 Ping Feb 10 2023 09:21 AM
C1121X-8PLTEP#clear ip dhcp conflict *
C1121X-8PLTEP#show ip dhcp conflict
IP address Detection method Detection time VRF
Conflict table is now empty.
02-10-2023 03:45 AM
I found the problem.
There was this entry in the ios config
app-hosting appid guestshell
app-vnic management guest-interface 0
guest-ipaddress 10.0.1.254 netmask 255.255.255.0
end
I dont use the "app-hosting" capability on the Cisco 1100 router...and it appears to be bad news for DHCP scopes. Maybe carves out a chunk of address range for it's self? I dont know.
But as soon as I removed with
C1121X-8PLTEP(config)#no app-hosting appid guestshell
I got my DHCP pool back, and the DHCP exclusion had disappeared.
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