• Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 848
  • Last Modified:

Erratic IP address/DHCP Problems happening across the network


We are experiencing very erratic network problems which include the following list which may or may not have any relation to each other:

1) Users getting the pop up message that says "there is an IP address conflict with another system on the network."  They can still usually access the internet.

2) Users whose network just stops working.  They have an IP address, but they cant go anywhere.  Usually a /release /renew fixes it

3) When you open up the DHCP server manager, under Address Leases, where all of the computer names and ip address leases are listed, there are all these "bad addresses".  Under "name" where computer name is, it says BAD_ADDRESS and under Description it says This address is already in use.  There are a TON of these BAD_ADDRESSES in our DHCP leases.  

4) In the DHCP Logs there are a ton of entries like this:
31,12/16/09,01:26:30,DNS Update Failed,,testpc.domain.lan,-1,

I dont know how common these "fails" are.  I've never looked into a DHCP log before.
We restarted the DNS and DHCP service, and it is doing the same thing.  

5) There is one DNS Even log error from 12/15.  It is Event ID 4015 with a description:

The DNS server has encountered a critical error from the Active Directory. Check that the Active Directory is functioning properly. The extended error debug information (which may be empty) is "". The event data contains the error.

6) Application log error: EventID 1004. Description: Reporting queued error: faulting application tcpsvcs.exe, version 5.2.3790.0, faulting module unknown, version, fault address 0x00000000.

I have never seen anything like this happen before.  About 1/4 of the company seems to be effected.  Nothing was changed recently to our servers.  Our lease time is 24 hours.

If there is any other info I can grab, please let me know!
3 Solutions
nociSoftware EngineerCommented:
Are there more that one DHCP server active in the network?
are there fixed addresses used by some systems that overlap the DHCP address range?

If a system detects it's address as being used it is required to instantly shut up and release a rental (DHCP) address.  So every time one address is doubly used one system goes down. timing decides which one.
Do you have a large enough scope to handle the PC's on the LAN?

We have noticed that the BAD_ADDRESSES on our LAN are related to iPhones and other smart phones that grab IP addresses and then do not release them properly. They generally are wiped out within a few days and released again. Most likely, your BAD_ADDRESSES are being held so you are being limited by the number of DHCP addresses you can hand out, hence the duplicate IP addresses.

I suggest changing the lease time to something less that 24 hours if you have a lot of smart phone users grabbing IP addresses.
Have you looked into conflict detection on the scope? have had a similar problem this helped, but didnt fix entirely.

If your going to shortern the scope for the dubious devices using dhcp i would look into having a user class for your desktops.

last of all do you have any VOIP on your network?
mirchevskyAuthor Commented:
Although not 100% sure the cause, I think all comments were very likely causes.  There werent any other DHCP server or added routers (we also had VLANs, so additional DHCP servers would have been extremely unlikly), but i think there were some overlapping IP addresses as well as a few smart phones.  After deleting all of the bad addresses and resolving some possible overlaps, Only one BAD Address showed up in DHCP in a week.  Thanks folks!!!!!!!
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

Join & Write a Comment

Featured Post

Cloud Class® Course: CompTIA Cloud+

The CompTIA Cloud+ Basic training course will teach you about cloud concepts and models, data storage, networking, and network infrastructure.

Tackle projects and never again get stuck behind a technical roadblock.
Join Now