03-19-2014 02:57 PM
I have a SG300-28P running 1.3.7.18 which is configured in L3 mode. This unit is running its DHCP service for my LAN hosts.
I've only set up a part of my /24 LAN subnet as the DHCP scope and have statically configured a number of LAN hosts to use specific IP addresses in this subnet, based on MAC address. For these reserved addresses I have used addresses outside the range used for the DHCP scope.
Here's an example:
ip dhcp server
ip dhcp pool host some-host-1
address 192.168.1.10 255.255.255.0 hardware-address b8:c7:5d:c7:f9:5e
exit
ip dhcp pool host some-host-2
address 192.168.1.11 255.255.255.0 hardware-address 20:c9:d0:9a:a2:fb
exit
ip dhcp pool network LAN
address low 192.168.1.201 high 192.168.1.253 255.255.255.0
domain-name home.local
default-router 192.168.1.1
dns-server 208.67.222.222
exit
However, what I'm seeing is the static hosts are being allocated addresses from the 192.168.1.201 thru 253 block (with the MAC Address/Client Identifier being shown with the correct MAC address but with a "01:" prefix).
Also I'm seeing a few (declined) entries which look similar to this "192.168.1.210 Client Identifier c0.a8.6f.e2 2014-Mar-18 12:01:24 Dynamic Declined", i.e. with a MAC address with just a XX.XX.XX.XX hex format.
Any thoughts.
03-19-2014 08:34 PM
Hi Ian, I believe you may not be using client identifer correctly. Use the client-identifer command and affix the 01 or the 00 in the command string.
client-identifer 01:20:c9:d0:9a:a2:fb
See if this will work.
03-20-2014 02:15 AM
Hi Tom,
I changed my statics from "hardware address <mac address>" to "client identifier 01:<mac address>" and that seems to work. What I don't understand is what was wrong with my MAC address configuration.
Also I'm still seeing some strange declined entries with short MAC addresses (i.e. XX.XX.XX.XX).
Thanks again.
03-20-2014 01:14 PM
I've done some more testing.
So using "address <ip-address> <subnet> hardware-address <mac address>" doesn't work.
Using "address <ip-address> <subnet> client-identifier 01<mac address>" does match the IP to the MAC but then the default gateway & dns settings are not inherited from the DHCP scope.
so I have to have configuration like this for every static host:
ip dhcp pool host <name>
address <ip-address> <mask> client-identifier 01<mac-address>
default-router <ip-address>
dns-server <ip-address>
exit
03-20-2014 04:31 PM
Hi Ian,
I did test this issue with my own switch. I got same issue as well. Please contact Cisco support center. 1-866-606-1866
Thanks,
Moh
06-07-2015 02:57 PM
I am having almost the same problem on Cisco SG300-28.
-Single default VLAN1 in L3 with 192.168.100.x/24 network, Switch IP 192.168.100.254/24
-Router/ISP modem's running NAT with LAN IP 192.168.100.1/24
-DHCP configured and assigning IP addresses to client machines from start of pool
-But static reservations for client machines is NOT working with MAC/hardware addresses, haven't tried with Client IDs yet.
Q1-Is only option to configure static reservations is through client IDs?
Q2-If so what will be the client IDs for MacBookPro, iphones and android devices? (I understand that windows devices have client IDs as 00 & 01:MACaddress
Q3-Do I have to make each static entry with Default-Router & DNS for all devices when using Client IDs? (I already have pool configured to assign default gateway 192.168.100.1 and dns 8.8.8.8 , which works well with dynamic DHCP clients)
P.S. I am doing all configuration through GUI, am I missing out on any important feature via GUI?
FJQ
11-08-2015 01:00 PM
ok - found a solution to a very similar, but not quite the same issue. So if someone has issues with assignind static ips via DHCP take a look at this post:
https://supportforums.cisco.com/discussion/11822701/sg500-dhcp-server-does-not-assign-predefined-static-ip-addresses-hosts
Long way short: Don't enter a "Client Name". That makes the difference!
Works like charm then... THANK YOU for this.
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