IP Hell

[Sabrina The Turd Polisher]

I know enough about networking to be dangerous. I kinda grasp the idea. And I know that it's almost esoteric in nature.
So here's my question:

What would cause a Mac to be sitting idle to display a message that it's IP address has been taken by another user?
We had to renew the DCHP lease to get a new address and the mac had it's connectivity again.

Moments before that happened the Mac hooked up to our plotter did the same thing.

Any ideas as to what's going on? We've been having IP issues for a couple weeks now. Not just the macs, seems everyday there's some sort of conflict we're chasing down.
currently Prepress can't see our server. we are dead in the water. I really should go to the beach today. 
Bad switch?

Here's a possible clue. 2 Friday's ago our service was disconnected by comcast, we had it restored about an hour later. This is also when our problems seem to have started.


any info into this would be helpful and a loaded shotgun...thanks. 

[mwc]

Too many option here to get too specific....but for starters...

What is supplying your internal DHCP services? A local device I hope (router, airport base station, a computer?)
Make sure only 1 device is supplying DHCP services (fighting DHCP servers can cause havoc - as in 2 airport base stations on that same network with DHCP services ON at the same time?)
I usually apply static/manual IP addresses to my servers and printers to make sure they always have the same IP, then I let all the other workstations use DHCP.
Make sure the IP Range that your DHCP server is allocating IP's from does not use a range that would interfere with your static IP's when set.
Less than 255 devices in your network? this is easy to manage.
If you have over 255 devices on your network...I'm unsure how to move to that 'next' step in routing network ranges?

Be aware that a computer can use/grab multiple IP addresses if you have multiple network adaptors ON (i.e. wired and wireless on the same mac ON will have 2 IP's if both are hooked up)

[Sabrina The Turd Polisher]

Thanks for that input mwc!

[Joe]

Agree with everything MWC said. Especially the part about more than one DHCP server which could be your issue. You need to check all of your routers/switches to make sure only one of them has DHCP enabled.

Once you find the one you can always go into the router settings and force DHCP to use the same IP address for all of your devices each time they are booted. This give you the benefit of DHCP with the luxury of always having the same IP address.

Might be a good idea to reboot all of your network devices too while you are messing with it.

[Sabrina The Turd Polisher]

thanks Joe!

[Farabomb]

That's what I have to do here. I have DHCP running but I have all prepress's IP's locked so I know what's where and Prinergy needs a static IP.

When others pop in they get assigned from DHCP and I don't have to worry. I also have prepress isolated on it's own switch with the front office on another. That helped when the front office switch went tits up while I was away but I was still able to login to prepress and get things done.

Didn't really care that the front office couldn't check FB for a day or 2.

[Joe]

That's what I have to do here. I have DHCP running but I have all prepress's IP's locked so I know what's where and Prinergy needs a static IP.

When others pop in they get assigned from DHCP and I don't have to worry. I also have prepress isolated on it's own switch with the front office on another. That helped when the front office switch went tits up while I was away but I was still able to login to prepress and get things done.

Didn't really care that the front office couldn't check FB for a day or 2.

And the world didn't spin off its axis?

[Farabomb]

They thought the world was ending but after an hour on the phone trying to diag to see it was a conflict that I could remotely solve or a hardware failure I stopped giving a damn.

It's infuriating trying to get information from people who's computer knowledge ends at "the big button turns it on"

[Grimace]

That's what I have to do here. I have DHCP running but I have all prepress's IP's locked so I know what's where and Prinergy needs a static IP.

When others pop in they get assigned from DHCP and I don't have to worry. I also have prepress isolated on it's own switch with the front office on another. That helped when the front office switch went tits up while I was away but I was still able to login to prepress and get things done.

Didn't really care that the front office couldn't check FB for a day or 2.

And the world didn't spin off its axis?

Nice! Now where's the "like" button?

[Tracy]

we had a huge problem with our internet phones grabbing ip address'

[WharfRat]

Static is good for production machines.
For regular users on the "Domain"
you can have their machine running
 - get the IP address of it
 - and "reserve" that adddres
so the DHCP server does not 'Hand it out."

MSD

[gnubler]

and a loaded shotgun...thanks.

I can help you.