I am trying to set up a DHCP server on an SRX 345 device. The DHCP server should send back some options (bootfile, router, domain-names...). The DHCP is involved in the boot process so a static dhcp binding is used where every mac address has a mapped IP in the pool. The dhcp client requests the DHCP server for the first time during the pxe boot, it gets the correct IP that was mapped to it's mac so the client will use the TFTP-server option specified in the DHCP offer and download the boot file, kernel and the initramd
Juniper PCAP Flags [Ext, no-L2, In], PCAP Extension(s) total length 16
Device Media Type Extension TLV #3, length 1, value: Ethernet (1)
Logical Interface Encapsulation Extension TLV #6, length 1, value: Ethernet (14)
Device Interface Index Extension TLV #1, length 2, value: 35072
Logical Interface Index Extension TLV #4, length 4, value: 74
-----original packet-----
PFE proto 2 (ipv4): (tos 0x0, ttl 20, id 1, offset 0, flags [none], proto: UDP (17), length: 576) 0.0.0.0.bootpc > 255.255.255.255.bootps: [udp sum ok] BOOTP/DHCP, Request from ac:1f:6b:47:6c:06, length 548, xid 0x6b476c06, secs 4, Flags [Broadcast] (0x8000)
Client-Ethernet-Address ac:1f:6b:47:6c:06
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Discover
Parameter-Request Option 55, length 36:
Subnet-Mask, Time-Zone, Default-Gateway, Time-Server
IEN-Name-Server, Domain-Name-Server, RL, Hostname
BS, Domain-Name, SS, RP
EP, RSZ, TTL, BR
YD, YS, NTP, Vendor-Option
Requested-IP, Lease-Time, Server-ID, RN
RB, Vendor-Class, TFTP, BF
Option 128, Option 129, Option 130, Option 131
Option 132, Option 133, Option 134, Option 135
MSZ Option 57, length 2: 1260
GUID Option 97, length 17: 0.0.0.0.0.0.0.0.0.0.0.172.31.107.71.108.6
ARCH Option 93, length 2: 0
NDI Option 94, length 3: 1.2.1
Vendor-Class Option 60, length 32: "PXEClient:Arch:00000:UNDI:002001"
Here it is fine we got the correct Ip that is mapped to the mac. Then, the client starts to download the root filesystem, at that time a new request is sent to the DHCP server (a new option 61: client identifier is specified). The problem occurs here the DHCP server assigns another address from the dynamic range to the client despite the static binding for that mac address is specified.
09:47:47.388131 In
Juniper PCAP Flags [Ext, no-L2, In], PCAP Extension(s) total length 16
Device Media Type Extension TLV #3, length 1, value: Ethernet (1)
Logical Interface Encapsulation Extension TLV #6, length 1, value: Ethernet (14)
Device Interface Index Extension TLV #1, length 2, value: 35072
Logical Interface Index Extension TLV #4, length 4, value: 74
-----original packet-----
PFE proto 2 (ipv4): (tos 0x10, ttl 64, id 0, offset 0, flags [DF], proto: UDP (17), length: 328) 0.0.0.0.bootpc > 255.255.255.255.bootps: [udp sum ok] BOOTP/DHCP, Request from ac:1f:6b:47:69:e4, length 300, xid 0xeec66346, secs 5, Flags [none] (0x0000)
Client-Ethernet-Address ac:1f:6b:47:69:e4
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Discover
Client-ID Option 61, length 19: hardware-type 255, 6b:47:69:e4:00:01:00:01:25:4c:13:ef:ac:1f:6b:47:69:e4
Parameter-Request Option 55, length 21:
RN, RB, Subnet-Mask, BR
MTU, Classless-Static-Route, Default-Gateway, Static-Route
Hostname, Option 119, Domain-Name, Domain-Name-Server
YD, YS, NTP, RP
Option 85, Option 86, Option 87, PRTR
MDHCP
MSZ Option 57, length 2: 1500
09:47:47.846931 Out
Juniper PCAP Flags [Ext], PCAP Extension(s) total length 16
Device Media Type Extension TLV #3, length 1, value: Ethernet (1)
Logical Interface Encapsulation Extension TLV #6, length 1, value: Ethernet (14)
Device Interface Index Extension TLV #1, length 2, value: 35072
Logical Interface Index Extension TLV #4, length 4, value: 74
-----original packet-----
58:00:bb:af:e7:42 > ac:1f:6b:47:69:e4, ethertype IPv4 (0x0800), length 321: (tos 0x0, ttl 64, id 35562, offset 0, flags [none], proto: UDP (17), length: 307) 10.22.102.1.bootps > 10.22.102.214.bootpc: [udp sum ok] BOOTP/DHCP, Reply, length 279, xid 0xeec66346, Flags [none] (0x0000)
Your-IP 10.22.102.214
Server-IP 10.22.100.11
Client-Ethernet-Address ac:1f:6b:47:69:e4
file "pxelinux.0"
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Offer
Lease-Time Option 51, length 4: 86400
Subnet-Mask Option 1, length 4: 255.255.255.0
Server-ID Option 54, length 4: 10.22.102.1
Default-Gateway Option 3, length 4: 10.22.102.1
Domain-Name-Server Option 6, length 8: 1.1.1.1,1.0.0.1
Any ideas? How to disable the client-id option on the DHCP server?