Hello,
I am using isc-dhcp stack version dhcp-4.3.5.
I am intending to use DHCPINFORM to get vendor-options from the DHCP
server that has offered me the ip.
My dhclient.conf is as below:
#Option 50 (Address Request) - Previously used IP Address (if available)
# automatically sent
#Option 53 (Message Type) - Includes all applicable Client -->
Server Options
# automatically sent
#sending vendor class in option 60
send vendor-class-identifier \""$VENDOR_ID"\";
#option 61 sends the backplane id as client identifier, used
at server to provide specific attrs
send dhcp-client-identifier \""$CLIENT_ID"\";
#request the params from server
#request subnet-mask, routers, broadcast-address,
vendor-encapsulated-options;
request vendor-encapsulated-options;
#dhcp inform
send dhcp-message-type 8;
From tcpdump, i am able to see that dhclient is sending:
[root@in-nelnx-dt ~]# tcpdump -i enp16s0 -vvXn port 67
tcpdump: listening on enp16s0, link-type EN10MB (Ethernet), capture
size 65535 bytes
17:15:50.369748 IP (tos 0x10, ttl 128, id 0, offset 0, flags [none],
proto UDP (17), length 328)
0.0.0.0.bootpc > 255.255.255.255.bootps: [udp sum ok] BOOTP/DHCP,
Request from 00:90:0b:76:00:cb, length 300, xid 0x94ab6216, Flags
[none] (0x0000)
Client-Ethernet-Address 00:90:0b:76:00:cb
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Inform
Lease-Time Option 51, length 4: 3600
Requested-IP Option 50, length 4: 192.168.2.213
Parameter-Request Option 55, length 1:
Vendor-Option
Vendor-Class Option 60, length 12: "MYDEPT%CARDTYPE"
Client-ID Option 61, length 18: hardware-type 50,
31:32:39:36:25:4d:41:39:30:31:33:35:31:30:30:38:39
0x0000: 4510 0148 0000 0000 8011 3996 0000 0000 E..H......9.....
0x0010: ffff ffff 0044 0043 0134 fcce 0101 0600 .....D.C.4......
0x0020: 94ab 6216 0000 0000 0000 0000 0000 0000 ..b.............
0x0030: 0000 0000 0000 0000 0090 0b76 00cb 0000 ...........v....
0x0040: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0050: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0060: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0070: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0080: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0090: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x00a0: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x00b0: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x00c0: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x00d0: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x00e0: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x00f0: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0100: 0000 0000 0000 0000 6382 5363 3501 0833 ........c.Sc5..3
0x0110: 0400 000e 1032 04c0 a802 d537 012b 3c0c .....2.....7.+<.
0x0120: 496e 6669 6e65 7261 254f 4c41 3d12 3231 MYDEPT%CARDTYPE=.21
0x0130: 3239 3625 4d41 3930 3133 3531 3030 3839 296%<SERIALNUM>
On checking the dhcpserver logs:
lnx-dt log]# tail -f messages
Feb 11 17:24:49 in-nelnx-dt dhcpd: DHCPREQUEST for 192.168.2.225 from
00:90:0b:4c:c8:e8 via enp16s0
Feb 11 17:24:49 in-nelnx-dt dhcpd: DHCPACK on 192.168.2.225 to
00:90:0b:4c:c8:e8 via enp16s0
Feb 11 17:25:00 in-nelnx-dt systemd-logind: Removed session 2838.
Feb 11 17:25:12 in-nelnx-dt systemd-logind: Removed session 2839.
Feb 11 17:25:19 in-nelnx-dt dhcpd: DHCPREQUEST for 192.168.2.213 from
00:90:0b:76:00:cb via enp16s0
Feb 11 17:25:19 in-nelnx-dt dhcpd: DHCPACK on 192.168.2.213 to
00:90:0b:76:00:cb via enp16s0
Feb 11 17:25:27 in-nelnx-dt dhcpd: DHCPINFORM from 0.0.0.0 via
enp16s0: ignored (null source address).
Feb 11 17:25:31 in-nelnx-dt dhcpd: DHCPINFORM from 0.0.0.0 via
enp16s0: ignored (null source address).
Feb 11 17:25:43 in-nelnx-dt dhcpd: DHCPINFORM from 0.0.0.0 via
enp16s0: ignored (null source address).
Feb 11 17:25:56 in-nelnx-dt dhcpd: DHCPINFORM from 0.0.0.0 via
enp16s0: ignored (null source address).
Feb 11 17:26:06 in-nelnx-dt dhcpd: DHCPINFORM from 0.0.0.0 via
enp16s0: ignored (null source address).
I observe the ciaddr is coming as 0.0.0.0 , which as RFC2131/2132,
should be valid value that contains the already offered IP.
I dont have relay, so I cant fill, giaddr.
But how do ensure to fill the ciaddr, from the dhclient.conf.
Also the script file:
https://github.com/greearb/dhcp-ct/blob/master/dhclient-scriptCan you please guide me how I can do that.
Thanks,
divakar
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