Please, is possible to do DNS updates with ISC kaa or another dhcp daemon?
Why am I asking? Because ISC dhcpd (not supported for two years now) - for
me version isc-dhcpd-4.4.3-P1 on Fedora 40 x86_64) seems to have problems
with crazy file bloat if some commands (especially log concat) are used
in event directives "on release" and/or "on expiry" - it seems that
the commands of these events dhcpd try to save to the dhcpd.leases file
and this can cause them to grow a lot, while the file itself can contain
nonsense.
What is interesting is that file verification (dhcpd -T) passes without
error on such a file full of nonsense.
Probably the same problem is also described on the Zentyal forum:
https://forum.zentyal.org/index.php?topic=35695.0
my example (based on the page
https://wiki.samba.org/index.php/Configure_DHCP_to_update_DNS_records ):
1) "on expire" and "on exit" only contain the execute command.
The dhcpd.leases file entry then looks something like this:
lease 192.168.17.10 {
starts 6 2024/08/24 10:14:26;
ends 6 2024/08/24 11:14:26;
cltt 6 2024/08/24 10:14:26;
binding state active;
next binding state free;
rewind binding state free;
hardware ethernet 88:a1:20:56:07:36;
uid "\001\210\241 V\0076";
set ClientName = "dhcp-192-168-17-10";
set ClientDHCID = "88:a1:20:56:07:36";
set ClientIP = "192.168.17.10";
set noname = "dhcp-192-168-17-10";
set vendor-class-identifier = "android-dhcp-9";
on expiry {
set ClientIP =
binary-to-ascii (10, 8, ".", leased-address) ;
execute ("/usr/local/bin/dhcp-ad-dyndns.sh", "delete", ClientIP, "",
"0");
}
on release {
set ClientIP =
binary-to-ascii (10, 8, ".", leased-address) ;
execute ("/usr/local/bin/dhcp-ad-dyndns.sh", "delete", ClientIP, "9");
}
}
2) "on expire" and "on exit" also contain a log command:
lease 192.168.1.253 {
starts 5 2024/08/23 18:01:57;
ends 5 2024/08/23 19:01:57;
cltt 5 2024/08/23 18:01:57;
binding state active;
next binding state free;
rewind binding state free;
hardware ethernet 88:a1:20:56:07:36;
uid "\001\210\241 V\0076";
set vendor-class-identifier = "android-dhcp-9";
set noname = "dhcp-192-168-1-253";
set ClientIP = "192.168.1.253";
set ClientDHCID = "88:a1:20:56:07:36";
set ClientName = "dhcp-192-168-1-253";
set isst = "dynamic";
on expiry {
set ClientIP =
binary-to-ascii (10, 8, ".", leased-address) ;
set ClientDHCID =
concat (concat (concat (concat (concat (concat (concat (concat
(concat (
concat
(
suffix
(
concat
(
"0",
binary-to-ascii
(16
,
8,
""
,
substring
(
hardware,
1,
1)
))
,
2)
,
":")
,
suffix
(
concat
(
"0",
binary-to-ascii
(16
,
8,
""
,
substring
(
hardware,
2,
1)
))
,
2)
),
":"),
suffix
(concat (
"0",
... (cca 400 similar garbage lines)
--
Thanks, Franta Hanzlik