Mac Thread, Ethernet DHCP Issues in Mac OS X Leopard in Technical; Dear fellow EduGeekers!
It isn't very often I need to ask for help, but unfortunately I'm very much so a ...
9th September 2011, 02:10 PM #1
- Rep Power
Ethernet DHCP Issues in Mac OS X Leopard
Dear fellow EduGeekers!
It isn't very often I need to ask for help, but unfortunately I'm very much so a "Microsoft Man" so when I'm faced with some college Intel Mac's which aren't getting DHCP addresses on their wired ethernet adapters - I just get stuck.
The Mac's take as long as 15 minutes to get an IP address. Only very occasionally does it give up and get an APIPA, for the most part when I click "Renew DHCP Lease" nothing appears to happen until out of the corner of my eye I notice it eventually populates the correct IP address.
Here's some facts:
- The DHCP server is our primary DC running our primary DNS. It is Windows Server 2003 R2.
- They are using the same VLAN and same DHCP server as our Windows clients - which work fine
- AirPort DHCP works fine. Again, this is the same DHCP server, but it is a different VLAN (this is currently our workaround)
- The problem has only reared its head in the last few weeks - prior to this it has been working for many years (albeit managed by my predecessor who was somewhat a "Mac Man" in comparison)
- The problem affects all Macs including Mac Mini, iMac and Macbook
- The firewall is set to "Allow all incoming connections" so unless there's a separately managed list of allowed/denied ports, then DHCP requests shouldn't be blocked by any firewall.
- Occasionally when I click on "Renew DHCP Lease" the previously assigned IP address, subnet mask and gateway address appear, then straight away disappears and then it takes 10-15 minutes to actually renew the lease.
Due to a lack of decent Mac knowledge, I can't say I have tried much. What I have tried is adding an address reservation for the Mac's on the DHCP server in the hope that this would accelerate the procedure, but unfortunately the same problem exists and all of the clients experience a long delay before getting an address.
On the Windows side of things I am going to inspect logs and events generated to see if I can relate anything to the error and perhaps setup some sort of network monitor on the DHCP server to see the actual requests coming in; or not as the case may be.
Apart from this, I am struggling and I hope it's something pretty basic I have missed and also I am stuck when it comes to the Mac side of things so if anyone can suggest literally anything to try (even if it is 1st day of school type stuff I might have missed - yes there is an ethernet cable connected, by the way :P) then it would be much appreciated.
IDG Tech News
9th September 2011, 02:30 PM #2
Not sure on what might be causing this, but if your Windows logs don't turn up much, the Macs' event logs can be found if you run the 'Console.app' found in /Applications/Utilities.
Hopefully you'll find a useful error message in there!
9th September 2011, 02:55 PM #3
- Rep Power
Thank you so much. Nothing seems to be reported by Windows, so seeing it from a Mac perspective is really useful.
I can't see anything interesting yet, but I might paste the part of the log from Renew DHCP Lease request to it actually getting the address. The time it takes does seem to vary. That last one took just 4 minutes. There are some Kerberos errors but this is at the end and I think it's just the binding between Open Directory on the Server to Active Directory and shouldn't be DHCP related.
4 minutes is a lot better, but still strikes me as too long, wouldn't you say?
9th September 2011, 02:59 PM #4
- Rep Power
The log from the mac:
Sep 9 13:44:44 it4622imac configd: setting hostname to "it4622imac.local"
Sep 9 13:44:44 it4622imac kernel: vmnet: VMNetDisconnect called for port 0xabfad00
Sep 9 13:44:44 it4622imac kernel: vmnet: bridge-en0: filter detached
Sep 9 13:44:44 it4622imac kernel: vmnet: bridge-en0: down
Sep 9 13:44:44 it4622imac kernel: vmnet: bridge-en0: detached
Sep 9 13:44:44 it4622imac kernel: vmnet: Freeing hub at 0x5cb5800.
Sep 9 13:48:27 it4622imac kernel: vmnet: VNetUserIf_Create: created userIf at 0x4aa8300.
Sep 9 13:48:27 it4622imac kernel: vmnet: VMNetConnect: returning port 0x4aa8300
Sep 9 13:48:27 it4622imac kernel: vmnet: Hub 0 does not exist, allocating memory.
Sep 9 13:48:27 it4622imac kernel: vmnet: Allocated hub 0x5cb5800 for hubNum 0.
Sep 9 13:48:27 it4622imac kernel: vmnet: VMNET_SO_BINDTOHUB: port: paddr 00:50:56:eb:da:82
Sep 9 13:48:27 it4622imac kernel: vmnet: Hub 0
Sep 9 13:48:27 it4622imac kernel: vmnet: Port 0
Sep 9 13:48:27 it4622imac kernel: vmnet: bridge-en0: got dev 0x48f4204
Sep 9 13:48:27 it4622imac kernel: vmnet: bridge-en0: up
Sep 9 13:48:27 it4622imac kernel: vmnet: bridge-en0: attached
Sep 9 13:48:27 it4622imac kernel: vmnet: VNetUserIfFree: freeing userIf at 0x4aa8300.
Sep 9 13:48:27 it4622imac configd: setting hostname to "it4622imac.domain.ac.uk"
Sep 9 13:48:32 it4622imac com.apple.KerberosAutoConfig: Couldn't find KerberosClient config record
Sep 9 13:48:34 it4622imac com.apple.KerberosAutoConfig: Couldn't find KerberosClient config record
Sep 9 13:48:44 it4622imac com.apple.DirectoryServices: Enter machine password:
Sep 9 13:48:45: --- last message repeated 1 time ---
Sep 9 13:48:45 it4622imac com.apple.DirectoryServices: Successfully registered hostname with DNS
Sep 9 13:48:54 it4622imac com.apple.KerberosAutoConfig: Kerberos configuration is up to date
9th September 2011, 08:19 PM #5
Have you tried a pc/laptop on the same network port? What sort of switch are these connected to - does it do POE or anything? Can you set up a mirrored port on the switch and use wireshark to see whats going on? Also do you have ipv6 set up on the network, or on the mac?
9th September 2011, 08:34 PM #6
- Rep Power
Hi thanks for the response.
Yes, the issue exists all over the college - we haven't yet had time to try it on a different VLAN wired. As I said earlier, it works fine on the Airport card on our wireless VLAN. The switches are all HP Procurve managed switches and they aren't POE capable.
I do need to do some more advanced monitoring, I think this will be the key.
IPv6 isn't configured on our network or on the Mac itself.
13th September 2011, 04:18 PM #7
- Rep Power
So I ascertained that in the Server 2003 logs there was a lot of NACK responses to DHCP requests coming from the Macs. Almost continuous until eventually it got its act together and found an address to use.
In DHCP, Conflict Detection Attempts was set at "0"
What seems to have resolved the issue is setting the above setting to 1. And now, on Macs, I am getting IP addresses within 20 seconds.
Does that make sense to anyone as to why changing that setting would resolve the issue?
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