Re: Cisco ISR 4331 won't assign static IPs.

ArkaGdynia · ‎03-01-2018

Hi,

I am trying to force Cisco ISR 4331 to assign static IPs to some of the hosts in the local network. It works partially, for instance for Linux laptop, HP printer, Windows laptops is fine, but not for Windows Server and WD NAS.

My configuration:

ip dhcp excluded-address 192.168.1.1
!
ip dhcp pool mypool
 network 192.168.1.0 255.255.255.0
 domain-name domain
 dns-server 192.168.1.1 8.8.8.8 
 default-router 192.168.1.1 
!
ip dhcp pool STATIC-99
 host 192.168.1.99 255.255.255.0
 hardware-address 68f7.2875.0899
 default-router 192.168.1.1 
 domain-name domain
 dns-server 8.8.8.8 192.168.1.1 
!
ip dhcp pool STATIC-100
 host 192.168.1.100 255.255.255.0
 hardware-address acbc.32cf.e9ff
 default-router 192.168.1.1 
 domain-name domain
 dns-server 8.8.8.8 192.168.1.1 
!
ip dhcp pool STATIC-109
 host 192.168.1.109 255.255.255.0
 hardware-address f481.39e3.afe4
 default-router 192.168.1.1 
 domain-name domain
 dns-server 8.8.8.8 192.168.1.1 
!
ip dhcp pool STATIC-110
 host 192.168.1.110 255.255.255.0
 hardware-address 6c40.08a6.06ca
 default-router 192.168.1.1 
 domain-name domain
 dns-server 8.8.8.8 192.168.1.1 
!
ip dhcp pool STATIC-141
 host 192.168.1.141 255.255.255.0
 hardware-address ac1f.6b20.f3a5
 default-router 192.168.1.1 
 domain-name domain
 dns-server 8.8.8.8 192.168.1.1 
!
ip dhcp pool STATIC-147
 host 192.168.1.147 255.255.255.0
 hardware-address 0090.a9e7.b624
 default-router 192.168.1.1 
 domain-name domain
 dns-server 8.8.8.8 192.168.1.1 
!
ip dhcp pool STATIC-151
 host 192.168.1.151 255.255.255.0
 hardware-address ac1f.6b02.513f
 default-router 192.168.1.1 
 domain-name domain
 dns-server 8.8.8.8 192.168.1.1 
!
ip dhcp pool STATIC-200
 host 192.168.1.200 255.255.255.0
 hardware-address b827.eb86.ca35
 default-router 192.168.1.1 
 domain-name domain
 dns-server 8.8.8.8 192.168.1.1 
!
ip dhcp pool STATIC-101
 host 192.168.1.101 255.255.255.0
 hardware-address b888.e31a.7e18
 default-router 192.168.1.1 
 domain-name domain
 dns-server 8.8.8.8 192.168.1.1

No matter how MAC address has been defined:

hardware-address b888.e31a.7e18

hardware-address b888.e31a.7e18 ethernet

or

hardware-address 01b8.88e3.1a7e.18

ciscorouter_SE#sh ip dhcp binding 
Bindings from all pools not associated with VRF:
IP address      Client-ID/              Lease expiration        Type       State      Interface
                Hardware address/
                User name
192.168.1.6     0100.90a9.e7b6.24       Mar 02 2018 11:33 AM    Automatic  Active     GigabitEthernet0/0/1
192.168.1.99    68f7.2875.0899          Infinite                Manual     Selecting  Unknown
192.168.1.100   acbc.32cf.e9ff          Infinite                Manual     Selecting  Unknown
192.168.1.101   b888.e31a.7e18          Infinite                Manual     Active     Unknown
192.168.1.109   f481.39e3.afe4          Infinite                Manual     Selecting  Unknown
192.168.1.110   6c40.08a6.06ca          Infinite                Manual     Selecting  Unknown
192.168.1.141   ac1f.6b20.f3a5          Infinite                Manual     Selecting  Unknown
192.168.1.147   0090.a9e7.b624          Infinite                Manual     Selecting  Unknown
192.168.1.151   ac1f.6b02.513f          Infinite                Manual     Selecting  Unknown
192.168.1.200   b827.eb86.ca35          Infinite                Manual     Selecting  Unknown

As you can see host 192.168.1.147 is defined as static (WD NAS), but still getting dynamic IP. No matter if binding table has been cleared or not.

Between router and local network there is a switch (not cisco), but there is no configuration on it. If I swap Cisco with cheap soho router like Dlink then it is fine.

Any idea what is wrong here?

Georg Pauwen · ‎03-01-2018

Hello,

you need to use the client-identifier option. Prepend 01 for the Ethernet media type, for example:

ip dhcp pool STATIC-99
host 192.168.1.99 255.255.255.0
client-identifier 0168.f728.7508.99
default-router 192.168.1.1
domain-name domain
dns-server 8.8.8.8 192.168.1.1

ArkaGdynia · ‎03-01-2018

I tried client-identifier earlier but with no media prefix and it didn't work neither for NAS nor for Linux or Windows laptops. However I'll try tomorrow and let you know.

Georg Pauwen · ‎03-01-2018

Actually, try both in the same pool, e.g.:

ip dhcp pool STATIC-99
host 192.168.1.99 255.255.255.0
client-identifier 0168.f728.7508.99

hardware-address 68f7.2875.0899
default-router 192.168.1.1
domain-name domain
dns-server 8.8.8.8 192.168.1.1

ArkaGdynia · ‎03-02-2018

It doesn't work either. Second line (hardware-address) has overwritten client-identifier.