Ask MetaFilter questions tagged with dhcp

DHCP giving clients addresses with prior DNS record

jmd82 — Fri, 02 Oct 2009 08:47:26 -0800

DHCP giving out IP address leases with pre-existing DNS entries for the wrong machine causing network chaos on a mixed windows & mac environment, and it's the macs who are having the problems. We have DHCP & DNS on a Windows 2003 server. Apple laptops (leopard) are bound to AD. The clients get a DHCP lease easily enough, but then at some point in the future (usually a few weeks, maybe less), they cannot log in or won't get settings from the server.

Have Apple support, and their response is the machine account is not authenticating with AD, so no log in. OK, so...

Upon investigation into DNS, it turns out that these client's DNS entry is actually tied to another PC's IP address. For instance, maclaptop.mydomain.com gets 192.168.1.1. However, the DNS record for 192.168.1.1 on the network is actually pc.mydomain.com. This is causing maclaptop.mydomain.com to try authenticating as pc.mydomain.com, which they are not and getting rejected. I am led to believe this from Console messages stating pc@mydomain.com cannot authenticate with kerberos.

Any thoughts or ideas on how to prevent this from happening? I can delete those individual DNS records and the clients can log in then properly, but at some point in the future, it'll loose its lease and get the address with a wrong DNS entry at some point.

What is wrong with my Internet connection?

Houyhnhnm — Sat, 22 Aug 2009 16:47:12 -0800

Every few minutes, my Internet connection drops out. It is a shared DSL connection that I connect to in my apartment (I have no access to the router). If I click the "Renew DHCP Lease" button in my Mac's preferences, it will work just fine for a few more minutes until it just stops again. What is the reasoning behind this, and how can I fix it so I don't have to "renew" my "lease" all the time?

Apple's self assigned IP address sucks

jeffburdges — Sun, 26 Jul 2009 10:58:42 -0800

Why does DHCP often suck on open WiFis? I occasionally have trouble with open wifis at bars and friend's places, thej just never issue an IP address via DHCP, and then my MacBook eventually makes up some worthless IP address.

I can often fix this problem by rebooting the router, but asking a waiter to reboot a router doesn't always get the best results. Are there more effective measures?

Mac OS X apparently doesn't put much thought into the self assigned IP address. Can an IP address be reasonably guessed by sniffing packets? If the router DHCP has crash, will the router itself de dead even with a good IP address guess?

Does anybody have a list of good IP address ranges for different routers?

Linux-based PXE image server?

Industrial PhD — Tue, 06 Jan 2009 11:15:32 -0800

Need to create a PXE image server that supports ghost images. Difficulty: Linux So my company makes a bunch of products and during testing I'm frequently breaking and needing to re-image the devices. This can be a pain as it is right now because my method is using bootable DVD's with ghost on it, and some of the devices don't have optical drives unless I hook up an external.

So I'd like to hook up a server that works with my DHCP switch to where i can set my device to network boot and it would start up in an interface where i can select the device and the image version, and it would all get pushed automatically.

I think this can be done with Windows Server, but for cost and geek reasons I'd rather use linux.

Thoughts?

Xbox 360 won't connect, thus limiting my 'rocking out' time.

cgomez — Sat, 19 Jul 2008 15:27:03 -0800

I've been using my Xbox 360 for almost a year without any networking problems. As of two days ago, it will not log into Xbox Live and the problem has gotten worse. I've been using the Xbox 360 on my network with an Apple AirPort Extreme (802.11n) and a cable internet connection without issue. On Thursday, I tried to get online and it wouldn't sign in - the network test failed on the MTU stage. I didn't have time to troubleshoot it then, so I waited until this morning. Now that I've been working with it, I tried swapping ethernet cables, power it off, along with my router and cable modem and such, now it won't even get an IP address. I even went so far as plug the 360 directly into the modem and restart the modem.

Is there a way to reset the 360 completely (and not lose my profile, downloaded content)? I'm certain that there is something on the 360 that is causing the problem. I've reset the 360 network settings to default, but they weren't change in the first place.

This is quite frustrating, please help. All logical attempts at remedying this have failed.

SOHO network with DHCP and static routing?

Ickster — Thu, 15 May 2008 20:09:38 -0800

In a home network, I'm using static routing on a router connected to my ISP connection, and added an additional router using DHCP. From the DHCP side, I'm able to connect to the internet, but am unable to reach any of the static addresses, nor can any of the static IPs reach through to the DHCP side. (How) can this be made to work? This is similar, but not identical to an earlier question. My difference is that I only have one public IP. Here's a quick outline:

cable modem (DHCP) --> Linksys (static routing; 192.168.100.1) --> Belkin (DHCP, 192.168.101.1)

I'm running a couple of internet-accessible services (web, svn, ftp) on a PC, hence the static routing. A file server is also located on the static side. PCs connected to the DHCP router are able to connect to the internet through the gateway at 192.168.1.1, but aren't able to see any other addresses on that subnet, so I can't reach my subversion server, file shares, make VNC connections, etc.

I should probably be able to figure this out myself, but networking gives me a headache and I haven't been able to put the right search terms together. Thanks for any help.

DHCP and VLAN configuration help needed.

odinsdream — Fri, 30 Nov 2007 09:56:52 -0800

DHCP and switch VLAN configuration help needed. I have a DHCP server connected to one port of a managed Netgear switch. I'd like to configure VLANs on this switch for separate office areas, each with their own subnet. I know how to do this with static addresses, since I would just manually configure each computer with the appropriate subnet. How can I hand these addresses out automatically with DHCP?

I'm also not sure how to make one port of the switch (connected to the DHCP server/router) part of each VLAN. I understand how to place a port into an untagged or tagged state, and have it be a member of a VLAN with another set of ports.

Much appreciated!

I got them ol' DHCP blues

nylon — Wed, 28 Nov 2007 16:59:26 -0800

My PC has completely lost interest in automatically obtaining an IP address from any network, by any method. My Toshiba Satellite Pro has been my tireless servant for over 3 years. Last week, while plugged into my ADSL router via an ethernet cable, I went to get a cup of tea. When I got back, 5 minutes later, I had 'limited or no connectivity' on the network. Restarting the router had no effect, restarting the PC had no effect. I can assign an IP address manually, and connect to the internet with ease and joy via both ethernet cable and PCMCIA wireless card and USB wireless dongle thingy. The moment I entrust the computer with the oh-so-difficult task of attempting automatic IP acquisition, the taskbar icon hangs at 'acquiring network address' and then gives up some minutes later.

Some additional facts:
There's another computer on the same network, it has no problem getting an automatic IP address. DHCP is enabled on the router, there's a wide enough range of available addresses, and it's been working fine for many months prior to this.
I've tried the PC on 3 different networks, with the same result - automatic is hopeless, manual is ok.
My DHCP service is active on the PC, and is set to automatically start on start-up.
WinSockFix does nothing to help.
Enabling NetBIOS over TCP/IP does nothing to help.
Google tells me that seemingly lots of other people have had similar problems, but either only with wireless, or because they forgot to enable DHCP on their router, or some other fairly straightforward thing that doesn't seem to apply to me. And lots of advice online has been stuff like 'try restarting the computer', or 'make sure your router is switched on'.

This is driving me insane, and while I can access the internet at home, because I know the right DNS gateways to use for manual DHCP, it means I can't use the laptop away from home.

What have I missed? Can anyone help?!

Help me get my new Airport to play nice with my old Linksys router

DandyRandy — Mon, 26 Nov 2007 22:10:24 -0800

I just picked up an Apple Airport Extreme and am attempting to integrate it into my home network, and my old router is jealous. My intent is to use the Airport to serve IP addresses to all my devices via DHCP, and use its wireless capabilities for my 802.11g computers (looking forward to 802.11n). I've pressed my old Linksys WRT54G into use providing wireless access to my 802.11b devices (2 wifi Internet radios), to isolate them from dragging down the .g devices' wireless access speeds. I've got the Linksys plugged into one of the LAN ports on the Airport, and the Linksys is getting its IP address (10.0.1.200) from the Airport's DHCP server. I've still got the DHCP server on the Linksys on, serving IP addresses in the 192.168.1.x range to my .b devices on the same subnet as the Airport. All that is working fine: all devices have internet access on their respective wireless networks.

The final step is for the .b devices to get their IP addresses from the Airport. That's what's not working. When I turn off the Linksys's DHCP server, the devices connected to its wireless network are getting IPs in the 169.254.x.y automatic private IP space. I've set the Linksys's config to both 'Gateway' (which is what it was when it was the only router on my network), and I've tried setting it to 'Router', with no further success.

Again, the Linksys' WAN address is getting 10.0.1.200 from the Airport's DHCP server, and I'm setting the Linksys LAN address to 10.0.1.201 (outside the Airport's DHCP range of addresses).

What am I missing here?

Multiple subnetted-and-failovered DHCP servers?

Blazecock Pileon — Thu, 15 Nov 2007 21:34:25 -0800

Can ISC's dhcpd run in both failover and multiple subnet modes? I'd like to run two DHCP servers, each in their own physical subnets.

I would also like to run them in failover mode, so that, if a DHCP server were to fail in subnet A, the other DHCP server in subnet B would take over for the failed DHCP server and serve up addresses for subnets A and B.

Any advice and/or sample configuration files? Again, not looking for failover or multiple subnet support alone — but both together. Thanks for any tips.

DHCP keeps timing out :(

Yelling At Nothing — Tue, 14 Aug 2007 21:03:02 -0800

What can I do to fix this DHCP problem with my Linksys router? It's been going on for a couple weeks, and I'm at a loss as to how to resolve it. Here's the skinny:

Comcast is the ISP, we're on a nice rented linksys router and motorola cable modem. There are five computers connecting to the router, 3 via ethernet and two wirelessly. The router's handling DHCP locally, but it seems to just die periodically.

What'll happen is this: I'll be surfing/downloading/gaming/whtaever, and I'll lose connectivity. Using windows to repair the connection fails, because it can't renew an IP address. Using ipconfig /release and /renew reveals that the DHCP server has timed out, and pinging the router at these times reveals packet loss. After five or ten minutes, everything works again.

This happens seemingly randomly, but frequently (probably once every hour or two, but possibly more often.)

I've tried most of the layman's router tech support stuff; unplug everything, powercycle, restart. Doesn't seem to help. Also ran through most of the tech support stuff on Linksys' website, and reset the MAC address and checked all the DHCP settings in the router control panel. Didn't have any luck there, either.

Anyone know what else could be causing this? I'd like to have it fixed.

Subnetting for Windows?

loquacious — Sun, 12 Aug 2007 23:23:54 -0800

How do I integrate several sub-networks for Windows/Samba compatibility in a rather complicated home-office environment? I'm having trouble getting shared drives/folders to appear to computers on different subnets, on a weird amalgam of chained routers and hubs.

However, what's the best way to integrate the IP structure of an increasingly complicated network to facilitate sharing and a small server?

How do I properly subnet a network so DHCP is properly propagated and the subnets don't clash and act transparently as one network?

Slingbox won't get IP Address from DHCP server

zachlipton — Fri, 30 Jun 2006 20:31:20 -0800

SlingboxNetworkingWoesFilter: I recently got a Slingbox, and while I am quite happy with the product in theory, I'm stalled with networking problems and the Slingbox fails to get an IP address from the DHCP server. Network routing is being provided by Mac OS X's Internet Sharing feature, and while the DHCP log shows numerous DHCP DISCOVER requests from the Slingbox, no IP address is ever assigned. Read on for details. The network itself is fine, as is the DHCP server. Normally, clients send a DHCP DISCOVER, the server responds, a DHCP REQUEST is logged, and an IP address is assigned. This works with my laptop, a Tivo, another laptop, and numerous other devices. When the Slingbox is connected to the network and reset, all I get is a steady stream of DHCP DISCOVER entries in the DHCP log:

Jun 30 20:13:42 desktop bootpd[215]: DHCP DISCOVER [en0]: 1,0:13:b6:1:87:ef

Thus far, Slingbox email support has been less than helpful, but I haven't had time yet during business hours to contact them when I could be at home and actually manipulate things. As far as I can tell, Google doesn't seem to report any known issues with the Slingbox and OS X's Internet Sharing.

If anyone has any sugguestions on how to get the DHCP server (Mac OS 10.4.7's included 'Internet Sharing') to serve up an IP to the Slingbox like it does for other devices, I'd really appreciate it.

DHCP Name Game

Gungho — Tue, 20 Jun 2006 12:27:38 -0800

If all else fails how do I get a mac running OS X 10.3.9 (Panther) to pull or request a DNS name. I have over 180 Macs online, and two won't register.(more inside) I have done all that I know such as resetting the Network control panel. renaming the computer, zapping PRAM, NVRAM and clearing all caches using cacheoutX. I have created a new Network location, and still the system will not register a name on our DHCP server. The name I want is 'gungho-mac' what it gets is dyn31123, which I assume is a dynamic name provided by the server. A sniff shows that the Mac never requests a name. Help me Obiwan, You're my only hope.

Give DHCP a chance.

Jonsnews — Thu, 06 Apr 2006 07:57:24 -0800

I would like to set up DHCP on our factory wide LAN. But I have some serious reservations. I need it to be secure, and I need to have control of who can get a DHCP license. What is the best way on a windows server 2000 (soon to be 2003) to set up a controlled DHCP environment.
We are both wired, and wireless, so just saying WEP encryption isn't a solution, as I would want our wired network to be AS secure as the wireless.
Is there a easy way to manage DHCP "liscenses" on a per MAC address basis.
To me, if this is possible it would be the best solution. It would be alot of work at first adding all the MACs of the equipment we have, but once done the maintaince should be minimal.
Also, is it easy to mix a static, and dymanic IP management. We have some equipment that would benefit from static IPs (which is our entire system now) like printers, and scanners and such, but then I would like all the desktops and laptops to be dhcp. We will also be going to a full Cisco IP phone system soon as well, so the DHCP issue is kind of hot right now. I want to do it, but still maintain control.
So any advice you guys have, software suggestions, and solutions are greatly apperciated.

Windows using a Mac Printer

ShooBoo — Thu, 16 Mar 2006 22:43:12 -0800

I have a printer on my MacMini and I want to be able to use it for print requests from my Windows XP laptop. I was able to get it working using CUPS and the MacMini's IP address, but the problem is that since the Mac is on a DHCP wireless network, the IP address can (and has) changed. Now printing from the laptop won't work. How do I identify the Mac from the laptop without using an IP address? I installed the CUPS drivers on my MacMini to get the XP laptop to be able to use the Mac's printer (Instructions can be found here).

On the laptop, I was able to connect to the printer using the Mac's IP address.

But now, the Mac's IP address has changed (the Mac is on the same wireless network as the laptop. I have a Linksys wireless router).

In order for the laptop to find the Mac regardless of its IP address, the Mac has to have a name that is resolved to the Mac's current IP address.

Things I have done so far on the Mac based on some web searching:
- Under Preferences/Sharing the computer name is "MacMini"
- Under Preferences/Network/TCPIP DHCP is selected and the DHCP client name is "MacMini"
- In /etc/hostconfig I have "HOSTNAME=MacMini"

The laptop hasn't been able to find the Mac with the name "MacMini" or "MacMini.local". The name doesn't resolve on the laptop.

Now on the Mac, the laptop's name doesn't resolve either, but the Mac is able to find the laptop by its name on the network in the Finder and I've been able to mount shared folders from the laptop to the Mac.

What do I need to do to be able to use the Mac printer from the laptop, regardless of the Mac's assigned IP address?

Thanks.

Expanding the home network

Fezboy! — Mon, 20 Feb 2006 15:19:30 -0800

This is probably an embarassingly easy question to answer, but when it comes to networking, I'm clueless. Can I use static IP + DHCP on same network using two routers—one wired/one wireless? I have a DSL connection with five (way too expensive) sticky/static IP addresses. I use the SBC-supplied DSL modem as a straight-through router. Three Linux boxes (two servers, one desktop) connect via the DSL modem/router, each claiming a static IP. That leaves one port on the DSL router and two IP addys.

I have recently picked up an iBook and, while I can hook up to that remaining port on the DSL modem/router, I'd like to do the wireless thing instead. I'd also like to do this using DHCP instead of assigning the laptop a static IP. I'm also getting to a point where just handing out IP addys to my collection of toys isn't going to work. it's a very nice problem to have and I'm definitely not complaining

Basically, can I conenct a wireless router into the remaining port on the DSL modem and configure it such that it runs a DHCP service while the other three connections still use the straight-through, static IP setup? Will the wireless router require one of the static IPs or can it just refer to the gateway IP?

BTW: I've looked into using one of the Linux boxes as a wireless DHCP service via a wireless PCI card but that looked exceedingly tedious, even for Gentoo. I'm sort of hoping this is the quick and easy answer to my problem.

DHCP printer hide and How do I keep my laser printer from playing hide-and-go seek with the router?

justkevin — Fri, 14 Oct 2005 11:04:27 -0800

How do I keep my laser printer from playing hide-and-go seek with a Dell TrueMobile router and XP? I have a Minolta Magicolor 2300 DL laser printer connected to my Dell TrueMobile 2300 router. The XP drivers for this printer want to access it as a Crown Port+, which requires an IP address.

Everytime the printer gets turned on, the dell router assigns it a different IP address (probably depending on what else happens to be on the network at the same time). So then I have to go into printer setup (for each computer on the network) and tell XP to autodiscover the printer's new IP address.

Any suggestions for how to avoid this?

How can I setup Windows 2003 server using a Dynamic IP Address?

nserrano — Wed, 28 Sep 2005 08:13:40 -0800

I want to setup a Windows 2003 server using my dynamic IP address that I have from Comcast. How can I make this happen? I have a linksys Gateway (WCG200) that has the server and a few other computers connected to it. I am trying to setup a small server for my printing/web hosting/file sharing/remote access needs. I need to see how to setup my DNS & DHCP settings for this to happen. Also I have my own domain name which I would like to use. Can I use programs from companies like no-ip.com to setup my web site so if anyone types my registered domain it will find my site? Remember that I will be using a dynamic address. Or the last straw is to get a static IP address. Where can I do so(for the cheapest price)?

Our office Macs won't connect to new NetGear wireless router

trbrts — Fri, 24 Sep 2004 13:37:42 -0800

I just installed a new NetGear wireless router in the office. We are going to use the firewall on that router for the whole office. But, I can't get the Mac's in the office to connect. (More inside of course...) So, I set the Mac's to DHCP and it looks like they are getting an IP from the router. But, they still won't connect. The OS X Powerbook has no problem connecting to the wireless, but the older Mac's, OS 10 and 9, won't connect. All the Windows machines switched from static to fixed IP's fine. Obviously I'm not a Macintosh person. Any help would be greatly appreciated.

Help me find the log for Windows XP Pro's connection sharing

LukeyBoy — Wed, 25 Feb 2004 17:56:23 -0800

I use the Windows XP Professional Internet Connection Sharing to dish out my DSL access to a couple of people residing in the same location. How do I find just basic log information about this service? It magically dishes out DHCP access to them, but I can't even find how many IP addresses have been assigned, how many connections are active, and so on.

Easy Windows XP switch between static IP and DHCP

LukeyBoy — Wed, 21 Jan 2004 04:04:40 -0800

In Windows XP is there any way to do a quick switch between DHCP and a given IP address? My home network connection uses DHCP - my work uses static. I've tried different hardware profiles with no success.