DHCP server not reusing expired leases

Hi,
I'm using DHCP server on SF300 switches for assigning IPs to guest clients.
DHCP lease expiration time is set to 1h, start address is 192.168.1.11 and end address is 192.168.1.20.
SF300 switch assigns all 10 IP addresses to different clients until pool gets exhausted. After 1 hour all DHCP leases become expired and I can verify this on address binding page.
Problem is new clients are connected after let's say 2 hours and they can't get IP address from SF300 switch because pool is exhausted and switch don't delete/reuse expired DHCP leases.
Is there any way to force switch to reuse or delete obsolete DHCP leases so new clients would be able to get valid IP address?

Hello there,
You can use the command (in privileged EXEC) clear ip dhcp binding X.X.X.X or just an * (asterisk) but if you use just the asterisk instead of an specific ip addresses, ALL bindings will be cleared, including active ones.
Hope this helps.

Similar Messages

DHCP server not reasigning IPs

Hello everyone,
We're having a big issue with our DHCP server (MAC OS X Server 10.6.4), because it runs out of IPs, because it's not reasigning the same IP to the same device.
The file /var/db/dhcp_leases show me the same MAC address and different IP, not freeing the anyone and thus, causing the server to stop giving IPs. We've currently managed to make a script to delete the leases db daily, but some days it's nt enough, any advise you could give us?
Some of the dchp_leases file:
ip_address=10.1.0.182
hw_address=1,0:26:bb:55:c4:e2
identifier=1,0:26:bb:55:c4:e2
lease=0x4cbda154
ip_address=10.1.0.181
hw_address=1,0:1b:63:b5:6a:de
identifier=1,0:1b:63:b5:6a:de
lease=0x4cbda0a3
name=MAC265
ip_address=10.1.0.180
hw_address=1,c4:2c:3:32:2d:23
identifier=1,c4:2c:3:32:2d:23
lease=0x4cbd9fe3
name=MAC265
ip_address=10.1.0.179
hw_address=1,c4:2c:3:32:2d:23
identifier=1,c4:2c:3:32:2d:23
lease=0x4cbd9f27
name=iPod
ip_address=10.1.0.178
hw_address=1,90:84:d:c4:72:2e
identifier=1,90:84:d:c4:72:2e
lease=0x4cbd9d08
Thanks in advance,
Message was edited by: gmestre

This looks more like a problem with network settings and not any hardware problem. Try to setup your LAN connection again. Recheck your network service provider settings (thru default access page 192.xxx.xxx.xxx, using wireless connection): check whether DHCP server is enabled.
If you are using mac address filter, add mac address of your LAN card to the allowed addresses in network settings in 192.xxx.xxx.xxx
3000 N100-0768DKU
XP Home 5.01.2600 SP2
Ubuntu 8.04(hardy)

DHCP Server not giving out IP Address to APPLE iPhone

Hi, First off, I hope this is the correct forum....
A little background, I have a very nice 16GB 3G iPhone (from Apple of course). It has no problem connecting to my wireless access point (cisco 1240). I have an old windows server that I can turn on as a dhcp server and it gets an address back right away, however my mac server (10.5) will no give it an address and I do not understand why. Here is the log.....
Mar 16 19:06:37 macserver bootpd[37021]: server starting
Mar 16 19:06:37 macserver bootpd[37021]: server name macserver.schmittg.com
Mar 16 19:06:37 macserver bootpd[37021]: interface en0: ip 192.168.1.75 mask 255.255.255.0
Mar 16 19:06:37 macserver bootpd[37021]: interface en2: ip 10.211.55.2 mask 255.255.255.0
Mar 16 19:06:37 macserver bootpd[37021]: interface en3: ip 10.37.129.2 mask 255.255.255.0
Mar 16 19:06:49 macserver bootpd[37021]: DHCP DISCOVER [en0]: 1,0:21:e9:5:d3:de <iPhone-5>
Mar 16 19:06:49 macserver bootpd[37021]: service time 0.008083 seconds
Mar 16 19:08:11 macserver bootpd[37021]: DHCP DISCOVER [en0]: 1,0:21:e9:5:d3:de <iPhone-5>
Mar 16 19:08:11 macserver bootpd[37021]: service time 0.003807 seconds
Mar 16 19:08:12 macserver bootpd[37021]: DHCP DISCOVER [en0]: 1,0:21:e9:5:d3:de <iPhone-5>
Mar 16 19:08:12 macserver bootpd[37021]: service time 0.000683 seconds
Mar 16 19:08:13 macserver bootpd[37021]: DHCP REQUEST [en0]: 1,0:21:e9:5:d3:de <iPhone-5>
Mar 16 19:08:13 macserver bootpd[37021]: service time 0.001844 seconds
Mar 16 19:08:24 macserver bootpd[37021]: DHCP DISCOVER [en0]: 1,0:21:e9:5:d3:de <iPhone-5>
Mar 16 19:08:24 macserver bootpd[37021]: service time 0.000587 seconds
Mar 16 19:08:25 macserver bootpd[37021]: DHCP REQUEST [en0]: 1,0:21:e9:5:d3:de <iPhone-5>
Mar 16 19:08:25 macserver bootpd[37021]: service time 0.000409 seconds
Mar 16 19:08:27 macserver bootpd[37021]: DHCP DECLINE [en0]: 1,0:21:e9:5:d3:de
Mar 16 19:08:27 macserver bootpd[37021]: dhcpd: host 1,0:21:e9:5:d3:de declines IP 192.168.1.227 from server 192.168.1.1
Mar 16 19:08:27 macserver bootpd[37021]: service time 0.001994 seconds
What is wrong?
Thanks!

I am having a similar problem:
---------------- Client Request --------------------
op = BOOTREQUEST
htype = 1
flags = 0
hlen = 6
hops = 0
xid = 20714
secs = 27
ciaddr = 0.0.0.0
yiaddr = 0.0.0.0
siaddr = 0.0.0.0
giaddr = 0.0.0.0
chaddr = 0:4:13:2a:2f:ed
sname =
file =
options:
Options count is 9
dhcpmessagetype (uint8): REQUEST 0x3
maxdhcp_messagesize (uint16): 0x224
requestedipaddress (ip): 192.168.1.66
server_identifier (ip): 192.168.1.200
host_name (string): m3-0004132A2FED
parameterrequestlist (uint8_mult): {0x1, 0x3, 0x6, 0xf, 0x21, 0x42, 0xa0}
vendorclassidentifier (string): snom-m3-SIP/01.25//10-Mar-09 16:36
client_identifier (uint8_mult): {0x1, 0x0, 0x4, 0x13, 0x2a, 0x2f, 0xed}
end (none):
bootpd[3138]: DHCP REQUEST [en1]: 1,0:4:13:2a:2f:ed <m3-0004132A2FED>
SELECT
state=SELECT
Sending: DHCP ACK (size 300)
bootpd[3138]: replying to 192.168.1.66
=================== Server Reply =====================
op = BOOTREPLY
htype = 1
flags = 0
hlen = 6
hops = 0
xid = 20714
secs = 0
ciaddr = 0.0.0.0
yiaddr = 192.168.1.66
siaddr = 192.168.1.200
giaddr = 0.0.0.0
chaddr = 0:4:13:2a:2f:ed
sname = ryan-perrys-computer.local
file =
options:
Options count is 8
dhcpmessagetype (uint8): ACK 0x5
server_identifier (ip): 192.168.1.200
lease_time (uint32): 0xdec
subnet_mask (ip): 255.255.255.0
router (ip_mult): {192.168.1.1}
domainnameserver (ip_mult): {208.67.222.222, 208.67.220.220}
domain_name (string): wha
end (none):
bootpd[3138]: ACK sent <no hostname> 192.168.1.66 pktsize 300
bootpd[3138]: service time 0.001879 seconds
destination address 255.255.255.255
---------------- Client Request --------------------
op = BOOTREQUEST
htype = 1
flags = 0
hlen = 6
hops = 0
xid = 11587
secs = 27
ciaddr = 0.0.0.0
yiaddr = 0.0.0.0
siaddr = 0.0.0.0
giaddr = 0.0.0.0
chaddr = 0:4:13:2a:2f:ed
sname =
file =
options:
Options count is 4
dhcpmessagetype (uint8): DECLINE 0x4
server_identifier (ip): 192.168.1.200
requestedipaddress (ip): 192.168.1.66
end (none):
bootpd[3138]: DHCP DECLINE [en1]: 1,0:4:13:2a:2f:ed
bootpd[3138]: dhcpd: IP 192.168.1.66 declined by 1,0:4:13:2a:2f:ed
marking host 192.168.1.66 as declined
state=<none>
bootpd[3138]: service time 0.001143 seconds
destination address 255.255.255.255

BEFW11S4 limited connectivity DHCP server not contacted

We have a network that has been running fine until a couple of days ago. We have changed no settings, yet now some of our wireless computers get the limited or no connectivity error. They are failing when trying to get the IP address assigned.
We're running 128 bit WEP encryption. My desktop machine which is hardwired to the router is fine, a hardwired network printer adapter is fine, and oddly enough two machines running Vista with a wireless connection are fine. It's my laptop, and a couple of my kid's laptops, all runnning XP Pro SP2, that are having problems.
I've tried ipconfig /release and /renew. The /renew times out, unable to contact the DHCP server.
I also tried the EasyLink Advisor software on my laptop. t tells me I need a wired connection.
One other piece of information; occassionally one of my sons have said they could not connect to the internet (on on of the XP machines) and I have powered the BEFW11S4 off an on, and then they were able to connect. I've never had this problem my laptop. But that's not working for anyone now.
I am at a loss as to why a network configuration that has been working perfectly well for over a month would selectively stop talking to computers with a certain operating system. Unless Microsoft has pushed an XP update recently that might have broken things?

have you tried upgrading / reflashing router's firmware .. if not , try it..after the upgrade , reset and reconfigure the router..check whether it makes any difference..

DHCP server not running on startup

Hello,
I installed Solaris 10u7 on my fileserver:
SunOS sunshine 5.10 Generic_139556-08 i86pc i386 i86pcI configured DHCP as follows:
dhcpconfig -D -r SUNWbinfiles -p /var/dhcp -a x.x.x.10,x.x.x.11 -d example.com -l 86400
dhcpconfig -N 192.168.0.0 -m 255.255.0.0 -t 192.168.0.1
pntadm -A 192.168.0.2 -m myhostname -y 192.168.0.0where x.x.x.10 and x.x.x.11 are my ISP's DNS servers.
At this point the DHCP server works beautifully. But when I reboot, the in.dhcpd process is not started (or quits immediately, I can't tell), and DHCP is:
DHCP server enabled.
DHCP server stopped.No combination of starting, stopping, or restarting the service with svcadm or dhcpconfig -S can start the server. The commands report success, but when I query, the serviceis enabled and stopped.
But if I just try running in.dhcpd manually, everything works again, until I reboot.
I'm new to Solaris so I'm not sure how to debug this. Any help would be appreciated!
Thanks!

Before the reboot, when everything still works fine:
svc:/network/dhcp-server:default (DHCP server)
State: online since Sat Sep 12 16:00:59 2009
See: in.dhcpd(1M)
See: /var/svc/log/network-dhcp-server:default.log
Impact: None.After the reboot:
svc:/network/dhcp-server:default (DHCP server)
State: offline since Wed Sep 30 13:13:36 2009
Reason: Service svc:/network/ntp:default is starting.
See: http://sun.com/msg/SMF-8000-GE
See: in.dhcpd(1M)
Impact: 1 dependent service is not running. (Use -v for list.)The log (a reboot appended the last 3 lines):
[ Sep 12 15:40:06 Enabled. ]
[ Sep 12 15:44:11 Rereading configuration. ]
[ Sep 12 15:46:18 Executing start method ("/usr/lib/inet/in.dhcpd") ]
[ Sep 12 15:46:18 Method "start" exited with status 0 ]
[ Sep 12 15:53:19 Stopping because service disabled. ]
[ Sep 12 15:53:19 Executing stop method (:kill) ]
[ Sep 12 15:54:47 Enabled. ]
[ Sep 12 16:00:59 Executing start method ("/usr/lib/inet/in.dhcpd") ]
[ Sep 12 16:00:59 Method "start" exited with status 0 ]
[ Sep 30 13:12:07 Stopping because service disabled. ]
[ Sep 30 13:12:07 Executing stop method (:kill) ]
[ Sep 30 13:13:36 Enabled. ]

SF300-24 DHCP Server not responding (worked once but not again)

Tried to get the new firmware DHCP Server option working but after turning it off and back on it doesn't seem to give any addresses anymore.
Anyone else having troubles or success actually using the SF300 v1.4 DHCP Server?
I even tried factory default reset but no luck.
When I did have it working everything was good but the older Cisco Meraki would not get an IP address so I had to revert to an older DHCP server. When I tried again today by turning the older server off and the SF300 back on, none of the Windows machines that previously would work would get an address.
Am running:
System Summary
System Information
System Operational Mode:
L2 Mode
System Description:
SF300-24 24-Port 10/100 Managed Switch
System Location:
Edit
System Contact:
Edit
Host Name:
switche2653d
Edit
System Object ID:
1.3.6.1.4.1.9.6.1.82.24.1
System Uptime:
0 day(s), 0 hr(s), 37 min(s) and 28 sec(s)
Current Time:
17:33:23;2014-Aug-06
Base MAC Address:
00:25:84:e2:xx:xx
Jumbo Frames:
Disabled
Software Information
Firmware Version (Active Image):
1.4.0.88
Firmware MD5 Checksum (Active Image):
66ab3618cb29023da5ce7c2177e6c3d4
Firmware Version (Non-active):
1.3.7.18
Firmware MD5 Checksum (Non-active):
1f59c2af2f50786e1a8a3146de42c867
Boot Version:
1.3.5.06
Boot MD5 Checksum:
da44c9c583e5a8a274f911c4d16f501e
Locale:
en-US
Language Version:
1.4.0.88
Language MD5 Checksum:
N/A
TCP/UDP Services Status
Edit
HTTP Service:
Enabled
HTTPS Service:
Enabled
SNMP Service:
Disabled
Telnet Service:
Disabled
SSH Service:
Disabled
Serial Number:
DNI15xxxxx
PID VID:
SRW224G4-K9 V01

Tried to get the new firmware DHCP Server option working but after turning it off and back on it doesn't seem to give any addresses anymore.
Anyone else having troubles or success actually using the SF300 v1.4 DHCP Server?
I even tried factory default reset but no luck.
When I did have it working everything was good but the older Cisco Meraki would not get an IP address so I had to revert to an older DHCP server. When I tried again today by turning the older server off and the SF300 back on, none of the Windows machines that previously would work would get an address.
Am running:
System Summary
System Information
System Operational Mode:
L2 Mode
System Description:
SF300-24 24-Port 10/100 Managed Switch
System Location:
Edit
System Contact:
Edit
Host Name:
switche2653d
Edit
System Object ID:
1.3.6.1.4.1.9.6.1.82.24.1
System Uptime:
0 day(s), 0 hr(s), 37 min(s) and 28 sec(s)
Current Time:
17:33:23;2014-Aug-06
Base MAC Address:
00:25:84:e2:xx:xx
Jumbo Frames:
Disabled
Software Information
Firmware Version (Active Image):
1.4.0.88
Firmware MD5 Checksum (Active Image):
66ab3618cb29023da5ce7c2177e6c3d4
Firmware Version (Non-active):
1.3.7.18
Firmware MD5 Checksum (Non-active):
1f59c2af2f50786e1a8a3146de42c867
Boot Version:
1.3.5.06
Boot MD5 Checksum:
da44c9c583e5a8a274f911c4d16f501e
Locale:
en-US
Language Version:
1.4.0.88
Language MD5 Checksum:
N/A
TCP/UDP Services Status
Edit
HTTP Service:
Enabled
HTTPS Service:
Enabled
SNMP Service:
Disabled
Telnet Service:
Disabled
SSH Service:
Disabled
Serial Number:
DNI15xxxxx
PID VID:
SRW224G4-K9 V01

AD, DHCP server not visible on network anymore

I've got a Domain with redundant AD servers - one physical, the other virtual. The physical is 32bit version of Server 2008, the virtual is a 64 bit version of Server 2008 R2. Everything have been working fine for about two years. I recently have been having
trouble with the physical server as it also serves as our backup server and our autoloader went AWOL on us. All that is back under control but shortly into that process I began noticing that the physical server kept dropping off the network - as in other computers
can't ping it, not can it ping other domain computers. It was a bit intermittent as it did finally connect after up and running for an hour or so - but that's not guaranteed either. It can see the internet so it appears to be a domain issue as opposed to a
network hardware issue.
I've looked through the system log but don't see anything that catches my eye.
Any suggestions?

Sorry for the delayed response. I thought I would receive email notifications, but alas.
The offending server (Glaurung) has a single network adapter - no pairing issues.
Nothing can ping either AD server - probably because it's not allowed by default as Jesper indicated. What I meant to convey was I cannot connect via Windows Remote Control when Glaurung initially boots up. The first time I try to connect, it does log in
but the service gets dropped and does not function for several hours (not sure exact time span). It does eventually work - as in the next day. Once it's back it seems stable.
I have not done any restores since initially setting up the redundant ADs (2 years ago).
Below are the two IPCONFIG commands.
HOST: Glaurung.basic.local
C:\Users\BUMonkey>ipconfig /all
Windows IP Configuration
   Host Name . . . . . . . . . . . . : Glaurung
   Primary Dns Suffix . . . . . . . : BaSIC.local
   Node Type . . . . . . . . . . . . : Broadcast
   IP Routing Enabled. . . . . . . . : No
   WINS Proxy Enabled. . . . . . . . : No
   DNS Suffix Search List. . . . . . : BaSIC.local
Ethernet adapter NIC2:
   Connection-specific DNS Suffix . :
   Description . . . . . . . . . . . : Intel(R) PRO/1000 XT Network Connection
   Physical Address. . . . . . . . . : 00-0B-DB-93-E5-AC
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes
   IPv4 Address. . . . . . . . . . . : 192.168.1.2(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Default Gateway . . . . . . . . . : 192.168.1.1
   DNS Servers . . . . . . . . . . . : 192.168.1.5
                                       192.168.1.2
                                       152.1.14.14
                                       152.1.14.53
   NetBIOS over Tcpip. . . . . . . . : Enabled
Tunnel adapter Local Area Connection* 9:
   Media State . . . . . . . . . . . : Media disconnected
   Connection-specific DNS Suffix . :
   Description . . . . . . . . . . . : isatap.{E67C2420-CF45-4BEE-A801-EA8F64B9E
30A}
   Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes
HOST: Lola-DC2.basic.local
C:\Users\BUMonkey>ipconfig /all
Windows IP Configuration
   Host Name . . . . . . . . . . . . : lola-DC2
   Primary Dns Suffix . . . . . . . : BaSIC.local
   Node Type . . . . . . . . . . . . : Broadcast
   IP Routing Enabled. . . . . . . . : No
   WINS Proxy Enabled. . . . . . . . : No
   DNS Suffix Search List. . . . . . : BaSIC.local
Ethernet adapter vNIC:
   Connection-specific DNS Suffix . :
   Description . . . . . . . . . . . : Microsoft Virtual Machine Bus Network Ada
pter #2
   Physical Address. . . . . . . . . : 00-21-9B-9C-DA-06
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes
   IPv4 Address. . . . . . . . . . . : 192.168.1.5(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Default Gateway . . . . . . . . . : 192.168.1.1
   DNS Servers . . . . . . . . . . . : 192.168.1.2
                                       192.168.1.5
                                       152.1.14.14
                                       152.1.14.53
   NetBIOS over Tcpip. . . . . . . . : Enabled
Tunnel adapter isatap.{984E1962-E7D6-411D-A989-ABCCE6589BE0}:
   Media State . . . . . . . . . . . : Media disconnected
   Connection-specific DNS Suffix . :
   Description . . . . . . . . . . . : Microsoft ISATAP Adapter
   Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes
Tunnel adapter Teredo Tunneling Pseudo-Interface:
   Media State . . . . . . . . . . . : Media disconnected
   Connection-specific DNS Suffix . :
   Description . . . . . . . . . . . : Teredo Tunneling Pseudo-Interface
   Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes
Thanks!

Problem with DHCP not flushing unused leases

We have a small network of approximately 40 devices that get IP addresses via DHCP. We have had at least one encounter where we used up all available 254 addresses in the DHCP pool. Come to find out, unused leases are not flushed.
Is there a utility or CRON job that should be running and perhaps has stopped, that will periodically flush unused leases? We had the lease time set for a couple days, and today changed it to 2 hrs, but it still isn't flushing.
Thanks

Hi RiBridges,
it might be to soon to check wether "flushing" occurs or not. As the man page of bootp states regarding DHCP:
"The server removes an expired lease entry only when it runs out of addresses, and needs to reclaim an address in order to fulfill a new request."
-Petra

DHCP lease issue for PPPoA sessions when using external DHCP server

We used to use the Cisco 7206VXR's DHCP server to hand out leases, and when we lost several hundred customers on a link, the router was able to get them up and connected with an IP address within minutes.
We switched over to using an external DHCP server so we could have more control over some extended DHCP options, as well as to aggregate all our DHCP traffic. Now, if we lose 100 DSL customers all at once, it takes 90 minutes for them to come up again. They come in a few at at time, until all 100 are back.
We see waves of RADIUS auth's in our RADIUS log (RADIUS has always been handled externally, so nothing changed there), and continuous streams of DHCP requests come in and DHCP offers go out. What seems to be happening is that a whole bunch of modems auth with RADIUS, request IP addresses, but for whatever reason, timeout when they don't all get their lease, drop the connection, and retry the whole process all over again. We purchased a dedicated DHCP server, thinking that was the bottleneck, but performance is about identical.
Here's our config:
interface Virtual-Template1
ip unnumbered Loopback11
ip helper-address a.b.c.d
peer default ip address dhcp
ppp authentication pap
ppp ipcp dns a.b.c.d e.f.g.h
ppp ipcp unique-address
My questions are:
- is there any performance issue with using an external DHCP server and PPPoA
- is there anything in our config that would cause such delays
Frank

GP:
No, the DHCP server is not across a WAN link; there is only a 10/100 switch in between the router and the DHCP server. There are no dropped packets on the interface.
I ended up opening a case with TAC about this issue. While I had the helper address configured in the template, TAC recommeneded that I specify the actual DHCP server with the command "ip dhcp-server x.x.x.x". This eliminates the DHCPBROADCAST (which I've verified). Perhaps the DHCP relay portion of the Cisco router is performed serially, instead of in parallel. By that, I mean, the next DHCPBROADCAST won't go out until there is the response for the first DHCPBROADCAST.
I'll know in a few days when we test again.
Frank

Window DHCP Server is not allocting IP to Voice Vlan

Hi,
I HAVE 3560 Switch, Over that two vlan configure Data & Voice respectively. Voice id Vlan 1 and Data Id Vlan 2.Routing is done on this switch and work as L3
DHCP Server is member of Data Vlan which is connected to another 3560 Switch L2. DHCP Server is reachable.On that both vlan configured.
Switch Port configure fr both Vlan ( Switchport access vlan 2 , Switchport voice vlan 1, Switchport mode access)
WHILE Connect any pc to port DHCP server assign ip frm Data Pool while Cisco Ip phones are not getting IP. OPTION 150 is configured in DHCP.
Over both interface IP Helper is configured and pointing to DHCP Server.
For testing point configure DHCP service on switch with voice pool range ;at that moment Cisco IP phone got the IP fron switch DHCP.
Now not able to understand why window dhcp server not assigning ip for Voice.
Both Vlan are in different subnet and having / 24.
Please guide

Hi,
Checked all configuration in network,apply packet tracer and found DHCP not responding on DHCP Req.
Replace DHCP server and now working fine. :)

DHCP server bad address issue

Hi,
I'm having an issue with ip address conflict or "bad_address"
I've checked for rogue dhcp server with wireshark. One issue i'm having is that the mac address of the device getting the bad_address issue on the dhcp server is only 8 characters. There is no such device like that on my network. This would be occuring every
other week. Removing it solved the problem, but how do i find the culprit of this problem?
Thanks.

What confuses me, is that it works fine at one site with all of your Windows 7 machines, but not the other. So something up with the DHCP Server? As I asked before, is it multihomed? If RRAS is installe on it, that constitutes multihoming, too.
OTH, Windows 7/Vista's DHCP Lease behavior is a bit different than XP. And keep in mind, we can't discount server side issues, yet, or we can look at this as a combo of the facts. In addition, if anything is on a VLAN, then that's another layer of "something"
else that we need to look at.
Anyway, here are my notes on Windwos 7/Vista DHCP lease behavior differences:
Windows 7 DHCP Lease Behavior is different than Windows XP upon startup
DHCP Client Behavior
http://blogs.technet.com/b/networking/archive/2009/01/29/dhcp-client-behavior.aspx
If the DHCP client obtained a lease from a DHCP server on a previous occasion, and the lease is still valid (not expired) at system startup, the client tries to renew its lease.
If, during the renewal attempt, the client fails to locate any DHCP server, it attempts to ping the default gateway listed in the lease, and proceeds in one of the following ways:
•If the ping is successful, the DHCP client assumes that it is still located on the same network where it obtained its current lease, and continues to use the lease as long as the lease is still valid. By default the client then attempts, in the background,
to renew its lease when 50 percent of its assigned lease time has expired.
•If the ping fails, the DHCP client assumes that it has been moved to a network where a DHCP server is not available. The client then auto-configures its IP address by using the settings on the Alternate Configuration tab. When the client is auto-configured,
it attempts to locate a DHCP server and obtain a lease.
As a workaround, you can force a Windows Vista or Windows 7 DHCP client to keep the old DHCP lease by adding registry key “DontPingGateway” if connectivity fails, see the resolution in the KB article below:
Windows Vista does not keep its DHCP IP address if a DHCP server is not available (works for Windows 7, too):
http://support.microsoft.com/kb/958336
Ace Fekay
MVP, MCT, MCITP Enterprise Administrator, MCTS Windows 2008 & Exchange 2007 & Exchange 2010, Exchange 2010 Enterprise Administrator, MCSE & MCSA 2003/2000, MCSA Messaging 2003
Microsoft Certified Trainer
Microsoft MVP - Directory Services
Complete List of Technical Blogs: http://www.delawarecountycomputerconsulting.com/technicalblogs.php
This posting is provided AS-IS with no warranties or guarantees and confers no rights.

WLC 5508, vlan select, reserved address in external DHCP server

Hi guys,
I have a deploy with a WLC 5508 version 7.0.116.0, APs mode local and vlan select feature enable. The issue is that the reserved IP address in external DHCP server not work. The DHCP contains a reserved IP address associates with mac address, but the assignement of IP is not match with de policies in DHCP. All others services operate normally.
This reserved assignment operate previusly to modificate the WLAN to vlan select feature. Help me to improve this situation.
Thanks.-
Best regards

Hello Abhishek, thanks for you quick answer....
the link was a document used for the deploy, but not especifict nothing about the reserved IP address for particular host. In other words, the reserved IP address (through MAC address) in external DHCP server not work when "vlan select" its enable.

Testing moving to new Windows Server 2008 R2 DHCP Server.

HI all,
I want to bring up a new DCHP server on an existing Windows Server 2008 R2 Domain Controller. The current DHCP server is a Windows 2003 Domain Controller. I have moved all the FSMO Roles to the new 2008 R2 domain controller
with the plan to eventually demote the 2003 server and take it off the network. I have the dhcp role installed on the new Windows Server 2008 R2 and have duplicated the exact settings (reservations, scope, etc.) from the old windows 2003 server
on the new 2008 R2 server. My plan was simply to disable the dhcp service on the old windows server 2003 and then authorize the new Windows Server 2008 R2 DHCP Server. However, after reading several articles, I understand that once you authorize
a new dhcp server, the old dhcp sever is unauthorized. I also read where several people had major issues with the new dhcp server not handing out IP Addresses even though the new dhcp server was authorized successfully. Since this is
a production network, I would like to employ the correct method to bring up the new dhcp server. Also, if there is a problem, is there an easy way to go back to the original dhcp server? Thanks for your help.
FD
Bob Andres

You can authorize multiple DHCP servers on a network.
You can activate and deactivate different scopes independently. So you can test DHCP functionality with a test scope.
Also, you can stop the old server in many ways that allow it to be online very rapidly: stop the dhcp server service, deactivate the scopes and yes even de-authorize the server.
My advice would be to built a test so you are confident (=very important) and not to fear the final onlining too much. DHCP is no rockets science. If you've replicated the configuration and are aware of possible IP Helper configurations on your routers/switches,
it should all work out fine.
MCP/MCSA/MCTS/MCITP

DHCP Server is not passing out DHCP Leases

I can't seem to figure out why DHCP server is not passing out DHCP lease a client?
Also I can't seem to figure out why NVI0 interface is UP? I have setup another box similarly and NVI0 is down on that and the DHCP server is working fine on that too. Strange!
I am working on CISCO 881 VPN Router...Please have a look at it and let me know. Thanks
Here is the configuration in the box...
sh run
Building configuration...
Current configuration : 6543 bytes
! Last configuration change at 17:09:54 CST Fri Sep 14 2012 by XXXXX
version 15.0
no service pad
service timestamps debug datetime msec
service timestamps log datetime msec
service password-encryption
hostname XXXXX
boot-start-marker
boot-end-marker
logging buffered 51200 warnings
aaa new-model
aaa authentication login default local
aaa authentication login vpn_xauth_ml_1 local
aaa authentication login sslvpn local
aaa authorization network vpn_group_ml_1 local
aaa session-id common
memory-size iomem 10
clock timezone CSTime -6
clock summer-time CST recurring
crypto pki trustpoint TP-self-signed-3079619067
enrollment selfsigned
subject-name cn=IOS-Self-Signed-Certificate-3079619067
revocation-check none
rsakeypair TP-self-signed-3079619067
crypto pki certificate chain TP-self-signed-3079619067
certificate self-signed 01
30820252 308201BB A0030201 02020101 300D0609 2A864886 F70D0101 04050030
31312F30 2D060355 04031326 494F532D 53656C66 2D536967 6E65642D 43657274
69666963 6174652D 33303739 36313930 3637301E 170D3132 30393134 31393231
32375A17 0D323030 31303130 30303030 305A3031 312F302D 06035504 03132649
4F532D53 656C662D 5369676E 65642D43 65727469 66696361 74652D33 30373936
31393036 3730819F 300D0609 2A864886 F70D0101 01050003 818D0030 81890281
8100993C D622004B F3AEA1E5 81106C28 36EC52D0 5435ABC3 8912095F 3641168A
B67D97AF AEB43CF3 00A00EB5 702FA355 9F58EBEF F42294DC 0E32CF40 E17D372A
3BC36401 55EDBA5C 910B7A51 89D709A8 7EAB3FF0 E4C99D34 CBE3F316 069C0E16
BC284055 35E3D762 463DABF6 852C4E7A D2EF45A4 21F08689 4DF17870 9E2A6C27
1BFB0203 010001A3 7A307830 0F060355 1D130101 FF040530 030101FF 30250603
551D1104 1E301C82 1A506F70 6C617276 696C6C65 2E796F75 72646F6D 61696E2E
636F6D30 1F060355 1D230418 30168014 64EA4CAE 2029E4C2 702584C6 B5732464
5C9DA38A 301D0603 551D0E04 16041464 EA4CAE20 29E4C270 2584C6B5 7324645C
9DA38A30 0D06092A 864886F7 0D010104 05000381 81006C27 96E06B83 04DBDA81
EEB0AF35 84ED370E A8C9694E F9B9326D 69CB1043 9C396D7B 760D252F 4881926D
878E434F 9AFC3E6D A5BF43F2 E619D6EC F45C039A 5FFB478F A99F7EE5 274E37D5
11976FDE 823FD1A9 700203E5 67A329B3 F4CF45F0 245757C8 E2349276 B13414D1
017616FA 38A40BA8 42545AC5 C7676D21 29E4F491 CADB
        quit
ip source-route
ip dhcp excluded-address 10.10.10.1
ip dhcp excluded-address 192.168.1.1 192.168.100.101
ip dhcp excluded-address 192.168.1.254
ip dhcp pool ccp-pool
   import all
   network 10.10.10.0 255.255.255.248
   default-router 10.10.10.1
   lease 0 2
ip dhcp pool Internal_Network
   network 192.168.1.0 255.255.255.0
   dns-server 192.168.100.254
   default-router 192.168.1.254
ip cef
ip domain name yourdomain.com
ip name-server 192.168.100.254
no ipv6 cef
license udi pid CISCO881-K9 sn FTX1604828T
username XXXXX privilege 15 secret 5 $1$QEcR$96cmvs/h/.05G6BnorcWG/
username XXXXX secret 5 $1$PQQ1$3.Vin0i/2uZ/KD0xEJ8GC.
crypto isakmp policy 1
encr 3des
authentication pre-share
group 2
crypto isakmp policy 2
encr 3des
hash md5
authentication pre-share
group 2
crypto isakmp client configuration group YYYYYYY
key XXXXX_XXXXX_XXXXX
pool VPN-Pool
acl VPN-Access-List
crypto isakmp profile vpn-isakmp-profile-1
   match identity group YYYYYYY
   client authentication list vpn_xauth_ml_1
   isakmp authorization list vpn_group_ml_1
   client configuration address respond
   virtual-template 2
crypto ipsec transform-set encrypt-method-1 esp-3des esp-sha-hmac
crypto ipsec profile VPN-Profile-1
set transform-set encrypt-method-1
interface FastEthernet0
interface FastEthernet1
interface FastEthernet2
interface FastEthernet3
interface FastEthernet4
description WAN_INTERFACE
ip address 192.168.100.3 255.255.255.0
no ip redirects
no ip unreachables
no ip proxy-arp
ip nat outside
ip virtual-reassembly
duplex auto
speed auto
interface Virtual-Template2 type tunnel
ip unnumbered FastEthernet0
tunnel mode ipsec ipv4
tunnel protection ipsec profile VPN-Profile-1
interface Vlan1
description VLAN1_INTERFACE
ip address 192.168.1.254 255.255.255.0
no ip redirects
no ip unreachables
ip nat inside
ip virtual-reassembly
ip tcp adjust-mss 1452
ip local pool VPN-Pool 192.168.1.151 192.168.1.200
ip forward-protocol nd
ip http server
ip http access-class 23
ip http authentication local
ip http secure-server
ip http timeout-policy idle 60 life 86400 requests 10000
ip nat inside source list 100 interface FastEthernet4 overload
ip nat inside source static tcp 192.168.1.100 21 192.168.100.3 21 extendable
ip nat inside source static tcp 192.168.1.100 80 192.168.100.3 80 extendable
ip route 0.0.0.0 0.0.0.0 192.168.100.254
ip access-list extended VPN-Access-List
permit ip 192.168.1.0 0.0.0.255 any
permit tcp host A.B.C.D host 192.168.1.100 eq ftp
permit tcp host A1.B1.C1.D1 host 192.168.1.100 eq ftp
permit tcp host A2.B2.C2.D2 host 192.168.1.100 eq ftp
permit tcp 192.168.1.0 0.0.0.255 host 192.168.1.100 eq ftp
permit tcp host A3.B3.C3.D3 host 192.168.1.100 eq ftp
permit tcp any host 192.168.1.100 eq XXX
access-list 23 permit 10.10.10.0 0.0.0.7
access-list 23 permit 192.168.1.0 0.0.0.255
access-list 100 permit ip 192.168.1.0 0.0.0.255 any
no cdp run
control-plane
banner exec ^C
% Password expiration warning.
Cisco Configuration Professional (Cisco CP) is installed on this device
and it provides the default username "cisco" for one-time use. If you have
already used the username "cisco" to login to the router and your IOS image
supports the "one-time" user option, then this username has already expired.
You will not be able to login to the router with this username after you exit
this session.
It is strongly suggested that you create a new username with a privilege level
of 15 using the following command.
username <myuser> privilege 15 secret 0 <mypassword>
Replace <myuser> and <mypassword> with the username and password you
want to use.
^C
banner motd ^C XXXXX-XXXXX VPN Router ^C
line con 0
exec-timeout 30 0
logging synchronous
no modem enable
line aux 0
line vty 0 4
access-class 23 in
privilege level 15
password 7 124A50424A5E5550
transport input telnet ssh
scheduler max-task-time 5000
end

Hi Jennifer,
I have gotten it resolved. Per your suggestion, I have turned on debug ip dhcp events and found that POOL EMPTY message. After little research, I found out that I have made a mistake in my excluded-address range.
I have had it as
ip dhcp excluded-address 192.168.1.1 192.168.100.101
It should have been
ip dhcp excluded-address 192.168.1.1 192.168.1.101.
It was a typo.
Thank you for the suggestion.
Srini

DHCP Client does not send host name to DHCP Server

Hello,
I installed Solaris 10 on VirtualBox and I cannot ping/ssh/telnet the virtual machine by its host name (even from the host computer) but only by it's ip.
I tried everything I could find on internet with no success (I don't want to add the hostname in every hosts file on every computer because it's not really professionnal)
I followed what said here: http://docs.oracle.com/cd/E26505_01/html/E27061/eyhuv.html#scrolltoc
Can someone has an idea of what I can do or why this does not work.
I installed a virtual Windows7 and an Ubuntu, and it worked perfectly.
Any help would be grantly appreciated.
Thank you
Here is my current configuration:
Oracle VM VirtualBox 4.3.8 (I choose "Oracle 10 10/09 and later (64 bit))
Oracle Solaris 10 1/13
Network: bridge with RealTek interface
NB: I don't have access to dhcp server on my netgear router (access is disabled by my ISP)
Files in /etc:
dhcp.e1000g0 (empty)
nodename (contains "thorgal")
nsswitch.conf has following lines:
hosts: files dns # Added by DHCP
ipnodes: files dns # Added by DHCP
networks:   files
protocols: files
rpc:        files
ethers:     files
netmasks:   files
bootparams: files
hostname.e1000g0 (contains "inet thorgal")
/etc/inet/hosts:
::1             localhost
127.0.0.1       localhost loghost
192.168.0.17    thorgal # Added by DHCP
/etc/default/dhcpagent:
REQUEST_HOSTNAME=yes
PARAM_REQUEST_LIST=1,3,6,12,15,28,43
.v6.PARAM_REQUEST_LIST=7,12,23,24,27,29
I also try "ifconfig e1000g0 dhcp release" with no success
the debugging of dhcpagent:
# pkill -x dhcpagent
# /sbin/dhcpagent -d1 -f &
1088
# ifconfig e1000g0 dhcp start
/sbin/dhcpagent: debug: insert_pif: e1000g0: sdumax 1500, hwtype 1, hwlen 6
/sbin/dhcpagent: debug: set_packet_filter: set filter 805869f (DHCP filter)
/sbin/dhcpagent: debug: get_smach_cid: getting default client-id property on e1000g0
/sbin/dhcpagent: debug: in state INIT; allowing start command on e1000g0
/sbin/dhcpagent: debug: ipc_action_start: started start (command 4) on e1000g0
/sbin/dhcpagent: debug: set_smach_state: changing from INIT to INIT_REBOOT on e1000g0
/sbin/dhcpagent: debug: dhcp_selecting: host thorgal
/sbin/dhcpagent: info: configure_v4_lease: setting IP netmask to 255.255.255.0 on e1000g0
/sbin/dhcpagent: info: configure_v4_lease: setting IP address to 192.168.0.17 on e1000g0
/sbin/dhcpagent: warning: configure_v4_lease: no IP broadcast specified for e1000g0, making best guess
/sbin/dhcpagent: info: configure_v4_lease: using broadcast address 192.168.0.255 on e1000g0
/sbin/dhcpagent: info: configure_v4_timers: e1000g0 acquired lease, expires Fri Mar 21 21:33:05 2014
/sbin/dhcpagent: info: configure_v4_timers: e1000g0 begins renewal at Fri Mar 21 09:33:05 2014
/sbin/dhcpagent: info: configure_v4_timers: e1000g0 begins rebinding at Fri Mar 21 18:33:05 2014
/sbin/dhcpagent: debug: set_smach_state: changing from INIT_REBOOT to PRE_BOUND on e1000g0
/sbin/dhcpagent: info: added default router 192.168.0.1 on e1000g0
/sbin/dhcpagent: debug: set_smach_state: changing from PRE_BOUND to BOUND on e1000g0
/sbin/dhcpagent: debug: configure_bound: bound e1000g0
/sbin/dhcpagent: debug: ipc_action_finish: finished start (command 4) on e1000g0: 0

During the Solaris installation process, you told it what the hostname was going to be and that you wanted that environment to exist with a dynamic IP address instead of a specific address that you desired.
When Solaris boots it broadcasts that hostname and waits for a DHCP server to be quasi-intelligent enough to award an IP address based upon a pre-configured list inside that DHCP server.   Hostname ABC would always get IP address 123 on subnet rst, hostname DEF would always get IP address 456 on subnet xyz, and so on and so on.
That's the fundamental process for proper (and thus secure) DHCP.
All your other environments (Windows, Debian, Ubuntu) are what might be thought of as "hacked for convenience" to get around that sort of network configuration. They take the lazy way to exist. That partial networking setup is good enough for a home network but would be miserably insecure in a corporate environment. Those choices are operating environments that are nice for end-user desktops but aren't Enterprise Class.
My suggestion?
Review the IP address range in your Netgear router's setup.
It is likely something like 192.169.0.1 through 192.168.0.50 and can be customized.
You probably don't have 50 devices on your network and probably will never have 50 simultaneous devices on your network.
... just do a reconfigure reboot and set your Solaris to use a static IP of 192.068.0.45
Then reboot and I predict your issue that prompted this forum thread will be gone.
That's how I've done it at home for many years, even when installing Solaris to bare metal (no virtualization).

DHCP server not reusing expired leases

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