This tool allows you to dynamically manage DHCP leases and hosts for
the isc-dhcp-server server. This tools is based on dhcp-lease-list command line.
This tool also use OMAPI protocole to dynamically inetract with the isc-dhcp-server.
Clone this repository in /usr/local/src then run from the folder install.sh
script. You can now run dhcp-admin. Help message should appear.
If command not run :
- Make sur your have the admin privileges.
- Make sur
/usr/local/sbinis in your environnement $PATH variable.
To work this tools need OMAPI service activate on your isc-dhcp-server. To activate
it insert those rules in the /etc/dhcp/dhcpd.conf file :
# List of available OMAPI key
# First key :
key my_key_name {
algorithm hmac-md5;
secret 0a0c4a3979592d1561582cf98a912c8f;
}
# Setup OMAPI servie
omapi-port 5000; # Wich port OMAPI will bind.
omapi-key my_key_name; # Key used by OMAPI service.
To generate key dhcp-admin give you à little script named omapi_keygen.
During first use run dhcp-admin init to setup OMAPI connection.
- 1 generate hash with
omapi_keygen
omapi-keygen hmac_md5 dhcp_admin_demo my_super_salt
creating ./omapi_key.pri and ./omapi_key.pub file
0a0c4a3979592d1561582cf98a912c8f
- 2 edit
dhcpd.conf
key dhcp_admin {
algorithm hmac-md5;
secret 0a0c4a3979592d1561582cf98a912c8f;
}
# Setup OMAPI servie
omapi-port 5000; # Wich port OMAPI will bind.
omapi-key dhcp_admin; # Key used by OMAPI service.
- 3 restart service
root@cl1-routeur /etc/dhcp # service isc-dhcp-server restart && service isc-dhcp-server status
● isc-dhcp-server.service - LSB: DHCP server
Loaded: loaded (/etc/init.d/isc-dhcp-server; generated)
Active: active (running) since Sun 2020-10-04 12:31:43 CEST; 25ms ago
Docs: man:systemd-sysv-generator(8)
Process: 6679 ExecStart=/etc/init.d/isc-dhcp-server start (code=exited, status=0/SUCCESS)
Tasks: 1 (limit: 1044)
Memory: 4.8M
CGroup: /system.slice/isc-dhcp-server.service
└─6691 /usr/sbin/dhcpd -4 -q -cf /etc/dhcp/dhcpd.conf eth1
- 4 verify omapi port
root@cl1-routeur /etc/dhcp # netstat -tunlp | grep dhcpd
tcp 0 0 0.0.0.0:5000 0.0.0.0:* LISTEN 6691/dhcpd
udp 0 0 0.0.0.0:67 0.0.0.0:* 6691/dhcpd
- 5 init your dhcp-admin tool
root@cl1-routeur /etc/dhcp # dhcp-admin init 127.0.0.1 5000 dhcp_admin 0a0c4a3979592d1561582cf98a912c8f
Make sur parametters are correct.
dhcp-admin doesn't implement any control.
Tool in now ready !
- 1 display lease
root@cl1-routeur /etc/dhcp # dhcp-admin show
HOST LIST :
TMP LIST :
LEASE LIST :
00:15:5d:01:65:07 192.168.1.50 cl1-webserver
00:15:5d:01:65:0a 192.168.1.52 cl1-docker
00:15:5d:01:65:0c 192.168.1.54 cl1-cli
- 2 select the lease you want to set static
root@cl1-routeur /etc/dhcp # dhcp-admin add -k cl1-webserver 192.168.1.2
...
omapi command interaction will be display
...
- 3 display new host
root@cl1-routeur /etc/dhcp # dhcp-admin show
HOST LIST :
00:15:5d:01:65:07 192.168.1.2 cl1-webserver
TMP LIST :
00:15:5d:01:65:07 192.168.1.50 cl1-webserver
LEASE LIST :
00:15:5d:01:65:0a 192.168.1.52 cl1-docker
00:15:5d:01:65:0c 192.168.1.54 cl1-cli
- 4 effective check with dhcp-lease-list
root@cl1-routeur /etc/dhcp # dhcp-lease-list
MAC IP hostname valid until manufacturer
===============================================================================================
00:15:5d:01:65:07 192.168.1.50 cl1-webserver 2020-10-04 10:53:54 -NA-
00:15:5d:01:65:0a 192.168.1.52 cl1-docker 2020-10-04 10:53:46 -NA-
00:15:5d:01:65:0c 192.168.1.54 cl1-cli 2020-10-04 10:58:48 -NA-
Here we can see the dhcp old lease for cl1-webserver is active.
- 5 new effective affter cl1-webserver reboot
root@cl1-routeur /etc/dhcp # dhcp-lease-list
Reading leases from /var/lib/dhcp/dhcpd.leases
MAC IP hostname valid until manufacturer
===============================================================================================
00:15:5d:01:65:0a 192.168.1.52 cl1-docker 2020-10-04 11:02:27 -NA-
00:15:5d:01:65:0c 192.168.1.54 cl1-cli 2020-10-04 11:02:55 -NA-
Here we can see the dhcp lease cl1-webserver doesn't appear any more.
- 6 The cl1-webserver has now 192.168.1.2 ip address
root@cl1-webserver /home/user # ip a | grep eth0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
inet 192.168.1.2/24 brd 192.168.1.254 scope global dynamic eth0
|!| Please very important!
Take a look of what are each *.db. Those files are displayed by dchp-admin show command line. The ip address from tmp.db are actually not auto-removed by the dhcp-admin command when you are sure about the new static lease is effective please remove the old lease manualy /usr/local/src/file/tmp.db files. If you don't do it this will potential cause some bug with dynamic lease with the same ip as thoses ip displayed in the tmp.db file.
- 7 check after manualy update
root@cl1-routeur /usr/local/src/dhcp_admin/file (git)-[main] # dhcp-admin show
HOST LIST :
00:15:5d:01:65:07 192.168.1.2 cl1-webserver
TMP LIST :
LEASE LIST :
00:15:5d:01:65:0a 192.168.1.52 cl1-docker
00:15:5d:01:65:0c 192.168.1.54 cl1-cli
The * .db files are utility files that allow you to keep a
trace on hosts and leases without having to analyze the file /var/lib/dhcp3/dhcpd.leases.
-
The
host.dbfile list all the configured host.
|!| Configured host do not significate active hote. The activation duration will depend of the previous lease expiration date. -
The
lease.dbfile list all the actifs lease without very newest static configuration. -
the
tmp.dbfile lists all the ip and mac addresses of the old lease which has not yet been converted to static.
(Static host is configured but the new lease is not active)
In folder exemple there is some files named line up those files are exemples about how it is possible to use function to create small process exection. Lot of comment are inside they explain each row.