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DHCP Stops responding after a couple days

slgarza
Level 1
Level 1

Hello Community, im having trouble getting DHCP to work on a L3 Core Cisco switch, it works properly but after a few days it stops responding, then i proceed to delete the dhcp pool and create it again solving the problem but only for a few days, any pointers or recommendation on what could it be? any help is greatly appreciated! many thanks!

 

this is the wireshark packet capture:

 

Frame 1: 342 bytes on wire (2736 bits), 342 bytes captured (2736 bits) on interface 0
Interface id: 0 (\Device\NPF_{8117FD5C-52CA-4B45-8137-0790F5C325D8})
Interface name: \Device\NPF_{8117FD5C-52CA-4B45-8137-0790F5C325D8}
Interface description: Wi-Fi
Encapsulation type: Ethernet (1)
Arrival Time: Aug 15, 2019 10:16:30.666225000 Central Daylight Time (Mexico)
[Time shift for this packet: 0.000000000 seconds]
Epoch Time: 1565882190.666225000 seconds
[Time delta from previous captured frame: 0.000000000 seconds]
[Time delta from previous displayed frame: 0.000000000 seconds]
[Time since reference or first frame: 0.000000000 seconds]
Frame Number: 1
Frame Length: 342 bytes (2736 bits)
Capture Length: 342 bytes (2736 bits)
[Frame is marked: False]
[Frame is ignored: False]
[Protocols in frame: eth:ethertype:ip:udp:dhcp]
[Coloring Rule Name: UDP]
[Coloring Rule String: udp]
Ethernet II, Src: IntelCor_dc:59:38 (a8:6d:aa:dc:59:38), Dst: Broadcast (ff:ff:ff:ff:ff:ff)
Destination: Broadcast (ff:ff:ff:ff:ff:ff)
Address: Broadcast (ff:ff:ff:ff:ff:ff)
.... ..1. .... .... .... .... = LG bit: Locally administered address (this is NOT the factory default)
.... ...1 .... .... .... .... = IG bit: Group address (multicast/broadcast)
Source: IntelCor_dc:59:38 (a8:6d:aa:dc:59:38)
Address: IntelCor_dc:59:38 (a8:6d:aa:dc:59:38)
.... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
.... ...0 .... .... .... .... = IG bit: Individual address (unicast)
Type: IPv4 (0x0800)
Internet Protocol Version 4, Src: 0.0.0.0, Dst: 255.255.255.255
0100 .... = Version: 4
.... 0101 = Header Length: 20 bytes (5)
Differentiated Services Field: 0x00 (DSCP: CS0, ECN: Not-ECT)
Total Length: 328
Identification: 0x7275 (29301)
Flags: 0x0000
Time to live: 128
Protocol: UDP (17)
Header checksum: 0xc730 [validation disabled]
[Header checksum status: Unverified]
Source: 0.0.0.0
Destination: 255.255.255.255
User Datagram Protocol, Src Port: 68, Dst Port: 67
Source Port: 68
Destination Port: 67
Length: 308
Checksum: 0xcf6e [unverified]
[Checksum Status: Unverified]
[Stream index: 0]
[Timestamps]
Dynamic Host Configuration Protocol (Discover)
Message type: Boot Request (1)
Hardware type: Ethernet (0x01)
Hardware address length: 6
Hops: 0
Transaction ID: 0x6923e70d
Seconds elapsed: 0
Bootp flags: 0x0000 (Unicast)
Client IP address: 0.0.0.0
Your (client) IP address: 0.0.0.0
Next server IP address: 0.0.0.0
Relay agent IP address: 0.0.0.0
Client MAC address: IntelCor_dc:59:38 (a8:6d:aa:dc:59:38)
Client hardware address padding: 00000000000000000000
Server host name not given
Boot file name not given
Magic cookie: DHCP
Option: (53) DHCP Message Type (Discover)
Length: 1
DHCP: Discover (1)
Option: (61) Client identifier
Length: 7
Hardware type: Ethernet (0x01)
Client MAC address: IntelCor_dc:59:38 (a8:6d:aa:dc:59:38)
Option: (12) Host Name
Length: 15
Host Name: DESKTOP-PROG09H
Option: (60) Vendor class identifier
Length: 8
Vendor class identifier: MSFT 5.0
Option: (55) Parameter Request List
Length: 14
Parameter Request List Item: (1) Subnet Mask
Parameter Request List Item: (3) Router
Parameter Request List Item: (6) Domain Name Server
Parameter Request List Item: (15) Domain Name
Parameter Request List Item: (31) Perform Router Discover
Parameter Request List Item: (33) Static Route
Parameter Request List Item: (43) Vendor-Specific Information
Parameter Request List Item: (44) NetBIOS over TCP/IP Name Server
Parameter Request List Item: (46) NetBIOS over TCP/IP Node Type
Parameter Request List Item: (47) NetBIOS over TCP/IP Scope
Parameter Request List Item: (119) Domain Search
Parameter Request List Item: (121) Classless Static Route
Parameter Request List Item: (249) Private/Classless Static Route (Microsoft)
Parameter Request List Item: (252) Private/Proxy autodiscovery
Option: (255) End
Option End: 255
Padding: 00000000

 

ill also attach a capture of when it works properly for reference:

 

Frame 22255: 370 bytes on wire (2960 bits), 370 bytes captured (2960 bits) on interface 0
Interface id: 0 (\Device\NPF_{8117FD5C-52CA-4B45-8137-0790F5C325D8})
Interface name: \Device\NPF_{8117FD5C-52CA-4B45-8137-0790F5C325D8}
Interface description: Wi-Fi
Encapsulation type: Ethernet (1)
Arrival Time: Aug 15, 2019 10:37:44.883231000 Central Daylight Time (Mexico)
[Time shift for this packet: 0.000000000 seconds]
Epoch Time: 1565883464.883231000 seconds
[Time delta from previous captured frame: 0.038054000 seconds]
[Time delta from previous displayed frame: 1.061145000 seconds]
[Time since reference or first frame: 1274.217006000 seconds]
Frame Number: 22255
Frame Length: 370 bytes (2960 bits)
Capture Length: 370 bytes (2960 bits)
[Frame is marked: False]
[Frame is ignored: False]
[Protocols in frame: eth:ethertype:ip:udp:dhcp]
[Coloring Rule Name: UDP]
[Coloring Rule String: udp]
Ethernet II, Src: IntelCor_dc:59:38 (a8:6d:aa:dc:59:38), Dst: Broadcast (ff:ff:ff:ff:ff:ff)
Destination: Broadcast (ff:ff:ff:ff:ff:ff)
Address: Broadcast (ff:ff:ff:ff:ff:ff)
.... ..1. .... .... .... .... = LG bit: Locally administered address (this is NOT the factory default)
.... ...1 .... .... .... .... = IG bit: Group address (multicast/broadcast)
Source: IntelCor_dc:59:38 (a8:6d:aa:dc:59:38)
Address: IntelCor_dc:59:38 (a8:6d:aa:dc:59:38)
.... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
.... ...0 .... .... .... .... = IG bit: Individual address (unicast)
Type: IPv4 (0x0800)
Internet Protocol Version 4, Src: 0.0.0.0, Dst: 255.255.255.255
0100 .... = Version: 4
.... 0101 = Header Length: 20 bytes (5)
Differentiated Services Field: 0x00 (DSCP: CS0, ECN: Not-ECT)
Total Length: 356
Identification: 0x7299 (29337)
Flags: 0x0000
Time to live: 128
Protocol: UDP (17)
Header checksum: 0xc6f0 [validation disabled]
[Header checksum status: Unverified]
Source: 0.0.0.0
Destination: 255.255.255.255
User Datagram Protocol, Src Port: 68, Dst Port: 67
Source Port: 68
Destination Port: 67
Length: 336
Checksum: 0x41fd [unverified]
[Checksum Status: Unverified]
[Stream index: 0]
[Timestamps]
Dynamic Host Configuration Protocol (Request)
Message type: Boot Request (1)
Hardware type: Ethernet (0x01)
Hardware address length: 6
Hops: 0
Transaction ID: 0xd2626714
Seconds elapsed: 10
Bootp flags: 0x8000, Broadcast flag (Broadcast)
Client IP address: 0.0.0.0
Your (client) IP address: 0.0.0.0
Next server IP address: 0.0.0.0
Relay agent IP address: 0.0.0.0
Client MAC address: IntelCor_dc:59:38 (a8:6d:aa:dc:59:38)
Client hardware address padding: 00000000000000000000
Server host name not given
Boot file name not given
Magic cookie: DHCP
Option: (53) DHCP Message Type (Request)
Length: 1
DHCP: Request (3)
Option: (61) Client identifier
Length: 7
Hardware type: Ethernet (0x01)
Client MAC address: IntelCor_dc:59:38 (a8:6d:aa:dc:59:38)
Option: (50) Requested IP Address (192.168.100.102)
Length: 4
Requested IP Address: 192.168.100.102
Option: (54) DHCP Server Identifier (192.168.100.1)
Length: 4
DHCP Server Identifier: 192.168.100.1
Option: (12) Host Name
Length: 15
Host Name: DESKTOP-PROG09H
Option: (81) Client Fully Qualified Domain Name
Length: 18
Flags: 0x00
A-RR result: 0
PTR-RR result: 0
Client name: DESKTOP-PROG09H
Option: (60) Vendor class identifier
Length: 8
Vendor class identifier: MSFT 5.0
Option: (55) Parameter Request List
Length: 14
Parameter Request List Item: (1) Subnet Mask
Parameter Request List Item: (3) Router
Parameter Request List Item: (6) Domain Name Server
Parameter Request List Item: (15) Domain Name
Parameter Request List Item: (31) Perform Router Discover
Parameter Request List Item: (33) Static Route
Parameter Request List Item: (43) Vendor-Specific Information
Parameter Request List Item: (44) NetBIOS over TCP/IP Name Server
Parameter Request List Item: (46) NetBIOS over TCP/IP Node Type
Parameter Request List Item: (47) NetBIOS over TCP/IP Scope
Parameter Request List Item: (119) Domain Search
Parameter Request List Item: (121) Classless Static Route
Parameter Request List Item: (249) Private/Classless Static Route (Microsoft)
Parameter Request List Item: (252) Private/Proxy autodiscovery
Option: (255) End
Option End: 255

 

best regards!

 

EDIT: attached the wrong packet

8 Replies 8

marce1000
VIP
VIP

 

 - Could be a software bug, check current release and or consider testing with more recent versions, if applicable. 

 M.



-- ' 'Good body every evening' ' this sentence was once spotted on a logo at the entrance of a Weight Watchers Club !

will try and keep posted, thanks for sharing!

cmarva
Level 4
Level 4

have you run debugs on dhcp on your core device?

will try and post back, thanks for sharing

Hello,

 

post the output of 'show ver'.

 

Does it also start to work again if you disable/enable the DHCP service ?

 

CoreSwitch(config)#no service dhcp

CoreSwitch(config)#service dhcp

Is it possible that your DHCP pool assigns a very long lease time (or even perhaps infinite)? This could lead to all addresses being used and no addresses available for assignment.

 

HTH

 

Rick

HTH

Rick

ive tried 7 and 30 day leases, also ipconfig /renew works on windows when dhcp is up

will try and post back the outcome and "show ver" thanks!

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