Ethernet Switching
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Ethernet Switching

DHCP server unable to lease IP

‎03-15-2020 02:48 AM

Hi,

We have EX4200 junos [12.3R3.4]

We are able to see end device mac in show ethernet switcing-table but did't get ip details in DHCP binding and show arp

Please suggest how to fix it.

 

SwitchEX4200# run show interfaces vlan.28
Logical interface vlan.28 (Index 118) (SNMP ifIndex 598)
Flags: SNMP-Traps 0x0 Encapsulation: ENET2
Input packets : 7650
Output packets: 87
Protocol inet, MTU: 1500
Flags: None
Addresses, Flags: Is-Preferred Is-Primary
Destination: 10.70.50.32/28, Local: 10.70.50.46, Broadcast: 10.70.50.47

SwitchEX4200# run show helper statistics
BOOTP:
Received packets: 349204
Forwarded packets: 531386
Dropped packets: 28
Due to no interface in DHCP Relay database: 0
Due to no matching routing instance: 0
Due to an error during packet read: 0
Due to an error during packet send: 28
Due to invalid server address: 0
Due to no valid local address: 0
Due to no route to server/client: 0

SwitchEX4200# run show configuration |display set |match dhcp
set system services dhcp pool 10.70.50.32/28 address-range low 10.70.50.33
set system services dhcp pool 10.70.50.32/28 address-range high 10.70.50.45
set system services dhcp pool 10.70.50.32/28 router 10.70.50.46

{master:0}[edit]
SwitchEX4200# run show configuration |display set |match 28
set system services dhcp pool 10.70.50.32/28 address-range low 10.70.50.33
set system services dhcp pool 10.70.50.32/28 address-range high 10.70.50.45
set system services dhcp pool 10.70.50.32/28 router 10.70.50.46
set interfaces vlan unit 28 family inet address 10.70.50.46/28
set vlans test vlan-id 28
set vlans test l3-interface vlan.28

{master:0}[edit]
SwitchEX4200# run show configuration |display set |match test
set interfaces ge-0/0/40 unit 0 family ethernet-switching vlan members test
set interfaces ge-0/0/41 unit 0 family ethernet-switching vlan members test
set interfaces ge-0/0/42 unit 0 family ethernet-switching vlan members test
set interfaces ge-0/0/43 unit 0 family ethernet-switching vlan members test
set interfaces ge-0/0/44 unit 0 family ethernet-switching vlan members test
set interfaces ge-0/0/45 unit 0 family ethernet-switching vlan members test
set vlans test vlan-id 28
set vlans test l3-interface vlan.28

SwitchEX4200# run show system services dhcp binding
IP address Hardware address Type Lease expires at
10.70.50.33 74:d2:7c:c2:7e:a2 dynamic 2014-03-26 04:29:06 UTC

{master:0}[edit]
SwitchEX4200# run show system services dhcp statistics
Packets dropped:
Total 35589
Bad hardware address 564

Messages received:
BOOTREQUEST 0
DHCPDECLINE 0
DHCPDISCOVER 12
DHCPINFORM 0
DHCPRELEASE 0
DHCPREQUEST 12

Messages sent:
BOOTREPLY 0
DHCPOFFER 12
DHCPACK 12
DHCPNAK 0

3 REPLIES 3
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Ethernet Switching

Re: DHCP server unable to lease IP

‎03-15-2020 09:57 AM

Step 1 - Upgrade to 12.3R12-S15, immediately or ASAP.  Then re-test.

 

Step 2 - If situation remains, open a Case with Juniper TAC - this functionality works and you either have config situation or something specific in your environment.  TAC can assist with either of these.

 

If you do not have TAC maintenance support for technical support, shame on your company, . . . I've got to believe what ever amount of time you (and potentially others; both = $$) looking at this would far outweight the actual cost for support, IMHO.

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Ethernet Switching

Re: DHCP server unable to lease IP

‎05-29-2020 07:28 AM

Hi Target,

 

There are many dropped packets in DHCP statistics.

SwitchEX4200# run show system services dhcp statistics
Packets dropped:
Total 35589

 

According to the next document, there are many reasons for this.

https://www.juniper.net/documentation/en_US/junos/topics/reference/command-summary/show-system-servi...

We need to check one by one.

Packets dropped

Total number of packets dropped and number of packets dropped because of:

  • Invalid hardware address

  • Invalid opcode

  • Invalid server address

  • No available address

  • No interface match

  • No routing instance match

  • No valid local addresses

  • Packet too short

  • Read error

  • Send error

Have you tried to collect tcpdump to see the DHCP communication, it can give you a clue.

 

Thanks!

Deimos.

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Ethernet Switching

Re: DHCP server unable to lease IP

‎05-29-2020 07:59 AM

Do you have DHCP traceoptions enabled ? Can you paste the output for "show system processes extensive" | except 0.0 

 

In case you have DHCP traceoptions enabled, disable it and then check.

 

Also, have you tried to monitor the incoming DHCP requests using monitor traffic and match for dhcp ?

 

 

BR,

Vishal

 

 

PS: Please accept my response as solution if it answers you query, kudos are appreciated too!

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