Issue
DHCP Server Option 43
Can someone share with me how to set options on dhcp server? I need to setup Option 43 for Cisco AP to find WiFi Controller.
In DHCP Server
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Responses (5)
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Accepted Answer
Hello Greg,
When setting extra options in dnsmasq, I suggest doing it in a file /etc/dnsmasq.d/any_name_you_like. You can see the format of the options in /etc/dnsmasq.d/dhcp.conf. It looks like you want something like:
Where enpXXX is your LAN interface. Repeat the line for multiple LAN interfaces.dhcp-option=enpXXX,43,some_string
The problem is the "some_string".
From this Cisco Doc, you may just want a comma separated, quoted IP address list. Try both quoted and unquoted.
After making your change, restart dnsmasq with "service dnsmasq restart". -
Accepted Answer
Nick, thanks for your assistance. This is what I have so far:
/etc/dnsmasq.d/wifi-dhcp-option
option vendor-class-identifier "Cisco AP c1815"
dhcp-option=enp2s0f1,43,"192.168.101.210"
I've restarted the dhcp service but the AP does not appear to grab the option. Can you confirm that I have typed the lines correctly? -
Accepted Answer
I'm not sure what the "option" line is doing. Does the dhcp-option need one or two IP's? I've tried googling around and not go anywhere particularly useful. You can see the dhcp-option parameter in the dnsmasq man pages. I would probably ask the Cisco people directly what they require.
From the man pages and your attempt, I'd try:
I can't work out if the vendor is required or not. If not specified, does it send option 43 to to every DHCP response?dhcp-option=enp2s0f1,vendor:Cisco AP c181543,192.168.101.210"
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Accepted Answer
Hi Gregory,
I was wondering if you had made any progress on this? I'd trying to do almost exactly the same thing, and have come up with using
dhcp-vendorclass=cisco,Cisco
dhcp-option=cisco,43,f1:04:c0:a8:00:ca
Using dhcpdump to sniff the DHCP requests and responses looks prommising:-
---------------------------------------------------------------------------
TIME: 2019-02-14 13:59:56.160
IP: 0.0.0.0 (60:73:5c:2f:40:af) > 255.255.255.255 (ff:ff:ff:ff:ff:ff)
OP: 1 (BOOTPREQUEST)
HTYPE: 1 (Ethernet)
HLEN: 6
HOPS: 0
XID: 000018b3
SECS: 0
FLAGS: 7f80
CIADDR: 0.0.0.0
YIADDR: 0.0.0.0
SIADDR: 0.0.0.0
GIADDR: 0.0.0.0
CHADDR: 60:73:5c:2f:40:af:00:00:00:00:00:00:00:00:00:00
SNAME: .
FNAME: .
OPTION: 53 ( 1) DHCP message type 3 (DHCPREQUEST)
OPTION: 57 ( 2) Maximum DHCP message size 1200
OPTION: 61 ( 7) Client-identifier 01:60:73:5c:2f:40:af
OPTION: 54 ( 4) Server identifier 192.168.0.1
OPTION: 50 ( 4) Request IP address 192.168.0.249
OPTION: 12 ( 16) Host name AP6073.5c2f.40af
OPTION: 55 ( 9) Parameter Request List 1 (Subnet mask)
6 (DNS server)
15 (Domainname)
44 (NetBIOS name server)
3 (Routers)
7 (Log server)
33 (Static route)
150 (???)
43 (Vendor specific info)
OPTION: 60 ( 14) Vendor class identifier Cisco AP c1040
---------------------------------------------------------------------------
TIME: 2019-02-14 13:59:56.160
IP: 192.168.0.1 (0:25:b3:25:dc:42) > 255.255.255.255 (ff:ff:ff:ff:ff:ff)
OP: 2 (BOOTPREPLY)
HTYPE: 1 (Ethernet)
HLEN: 6
HOPS: 0
XID: 000018b3
SECS: 0
FLAGS: 7f80
CIADDR: 0.0.0.0
YIADDR: 192.168.0.249
SIADDR: 192.168.0.1
GIADDR: 0.0.0.0
CHADDR: 60:73:5c:2f:40:af:00:00:00:00:00:00:00:00:00:00
SNAME: .
FNAME: .
OPTION: 53 ( 1) DHCP message type 5 (DHCPACK)
OPTION: 54 ( 4) Server identifier 192.168.0.1
OPTION: 51 ( 4) IP address leasetime 86400 (24h)
OPTION: 58 ( 4) T1 43200 (12h)
OPTION: 59 ( 4) T2 75600 (21h)
OPTION: 15 ( 13) Domainname XXXXXXXXXXXXX
OPTION: 43 ( 6) Vendor specific info f104c0a800ca ......
OPTION: 6 ( 4) DNS server 192.168.0.1
OPTION: 3 ( 4) Routers 192.168.0.1
OPTION: 1 ( 4) Subnet mask 255.255.255.0
---------------------------------------------------------------------------
The DHCP server seems to be passing the data I want it to, but the APs are still not finding the controller. -
Accepted Answer
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