From ch_geronimo at foxmail.com  Tue Dec  5 17:13:16 2023
From: ch_geronimo at foxmail.com (=?ISO-8859-1?B?Q0hfZ2Vyb25pbW8=?=)
Date: Wed, 6 Dec 2023 01:13:16 +0800
Subject: Linux server management debian 10 and centos dhcp service host-name
 based Client Classing
Message-ID: <tencent_0518F31E09B3BEE445DE4009A51896DE6605@qq.com>

I have already asked a question on serverfault(https://serverfault.com/questions/1149090/linux-server-management-debian-10-and-centos-dhcp-service-host-name-based-client), but I didn't receive any useful response. So, I'm reaching out to you for help. Sorry for bothering you.
I want to allocate a client's IP address based on the host-name provided by the client, but the results are often unpredictable.&nbsp;&nbsp;
I have tried to imitate the Client Classing in dhcpd.conf(5) by assigning&nbsp; &nbsp;
clients with host-name "Debian-xx" to the 192.168.100.0/24 subnet&nbsp; &nbsp;
clients with host-name "Centos-xx" to the 192.168.1.0/24 subnet.&nbsp;&nbsp;
I am using DHCP version 4.4.1. When I check the logs using "dhcpd -d", I noticed that the classing is not taking effect or there are errors. For example, the "Centos-xxx" clients might be assigned to the 192.168.100.0 or 192.168.255.0 subnet, and the assignments seem to be inconsistent.&nbsp;&nbsp;


This is the content of my dhcpd.conf file.


```
default-lease-time 10;
use-host-decl-names on;
max-lease-time 20;
authoritarive ;
log-facility local2;


class "centos-server"{
	match if (substring(option host-name ,0,6)="Centos") ;
}


class "debian-server"{
	match if (substring (option host-name&nbsp; ,0,6)="Debian") ;


}


subnet 192.168.0.0 netmask 255.255.0.0 {


	option routers 192.168.0.2;


	option subnet-mask 255.255.255.0;
	pool{
	allow members of "centos-server";
	range 192.168.100.1 192.168.100.254;
	}
	pool{
	allow members of "dbian-server";
	range 192.168.1.1 192.168.1.254;
	}
	pool{
	range 192.168.255.1 192.168.255.254;
	}


}
on commit {
log(debug, concat("test for&nbsp; &nbsp;",&nbsp; substring(option host-name,0,6 ) ));
&nbsp;if ( ( substring( option host-name , 0, 6 ) ="Debian") ) {
log(debug,"Debian!");
}
else if ( ( substring( option host-name , 0, 6 ) ="Centos") ) {
log(debug,"Centos!");
}
else {
log(debug,"i dont konw");
}


}


```
This is the content of my dhclient.conf


```
send host-name = gethostname();
request subnet-mask, broadcast-address, time-offset, routers,
	domain-name, domain-name-servers, domain-search, host-name,
	dhcp6.name-servers, dhcp6.domain-search, dhcp6.fqdn, dhcp6.sntp-servers,
	netbios-name-servers, netbios-scope, interface-mtu,
	rfc3442-classless-static-routes, ntp-servers;




```






I experimented with modifying the expression after "match if," such as using "or (1=1)," but the client may still not be assigned to that class.&nbsp;&nbsp;
I tried to see if it was an issue with "host-name" and "option host-name," but it doesn't seem to be the key issue.&nbsp;&nbsp;
I suspect there is an error in the conditional expression within the class, but the commit logs, I found that the log results alternated between "Centos!" and "I don't know".&nbsp;&nbsp;
I searched for related issues, such as this link [dhcpd class match on hostname or mac address](https://serverfault.com/questions/778719/dhcpd-class-match-on-hostname-or-mac-address), but it seems that the answers did not provide a good solution to the problem.&nbsp;&nbsp;
I want to know where my mistake lies, how to modify it, or if there are websites that provide solutions.&nbsp;&nbsp;


If you can provide assistance, I would be extremely grateful.
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