Getting IP thru DHCP w/o restart.

[Le Big Mac]

I have my iMac on a mini-home network with DHCP router. Sometimes my iMac won't pull an IP address on restart, or (today) it just drops it.

I can get a new address by restarting. But there must be a better way w/o a restart.

Please! Help me solve this simple problem. Thanks.

 

[FatTony]

You can try getting a new dhcp lease by changing your network settings to something without either ethernet or airport, hitting apply now, change the settings back, then hit apply now again. This should get your mac to request a new IP address. To make this easier, you could set up new locations and switching locations back and forth.

This suggestion only helps alleviate the symptoms. The best fix would be to figure out what is causing your iMac to drop its IP address. If you feel like trying to dig around and figure out the reason, let me know. I have a little bit of networking experience.

 

[Daveman Deluxe]

I recommend turning off DHCP and using manual IP addresses, particularly if you are using a wireless network. That's what I do, and I NEVER have DHCP problems, since I've turned off DHCP.

 

[mnkeybsness]

what router are you using? and some specs please?

in os x, and with most routers, you will be able to manually set an ip for your computer...such as i did with mine...

i left the router alone...don't mess with it...but you need to know your router's ip address, for instance, mine is 192.168.0.1...you should know what that is...you can double check by typing that in your browsers address bar.

then i went to the apple menu>system preferences...
clicked the network tab, and where it says "using dhcp", i changed that to "manually". now, if you haven't messed with the router's default settings, you can put your ip address to something like 192.168.0.2, anywhere through 192.168.0.299...(a router's default is to set the dhcp's to anything between 100 and 199)...note that the last digit needs to start with a 2 and be no more than three numbers long... now you need to leave the subnet to 255.255.255.0 and your router's ip address to what your routers ip is (EX mine is 192.168.0.1). your router should recognize this and it will no longer NEED to use dhcp.

 

[Le Big Mac]

Thanks all. It's a farrallon broadband router (I think that's the name--I'm at work--it's whatever their basic product was a couple of years ago). Sounds like the thing to do is set it up for manual IP.

The reason I had it set to DHCP is because my wife brings home her laptop from work (where it's configured for DHCP). THis way she can just plug in and go w/o changing anything on her laptop.

In principle, I should be able to set up manual IP for my mac and then DHCP for any other computers, right (making sure the address ranges don't overlap.). I just have to go figure out those settings and hit the admin panel.

 

[Daveman Deluxe]

Exactly right. Just set up your computer to keep a static manual IP address. I had to do that for awhile before I just turned off DHCP for security reasons. Make sure that it doesn't use an IP address that any other computer on your network does (computers using DHCP will often get the same address every time).

 

[mnkeybsness]

Originally posted by Daveman Deluxe
Exactly right. Just set up your computer to keep a static manual IP address. I had to do that for awhile before I just turned off DHCP for security reasons. Make sure that it doesn't use an IP address that any other computer on your network does (computers using DHCP will often get the same address every time).

the computer will not respond if you try to give it an IP in the dhcp range. therefore you will not have a problem. the default dhcp range is 192.168.0.100 to 192.168.0.199. if the last octet is set to start with the number 2, with any length of numbers starting with 2 up to 299 it will allow for a static IP.

 

[Le Big Mac]

Originally posted by Daveman Deluxe
Exactly right. Just set up your computer to keep a static manual IP address. I had to do that for awhile before I just turned off DHCP for security reasons. Make sure that it doesn't use an IP address that any other computer on your network does (computers using DHCP will often get the same address every time).

Hmm. Frustrating. I can't see a way to have a mixed environment. I set the manual ip to 192.168.0.2 (router is .1) and then set the DHCP range to be .3 to .51 (not that I need the full range). Anyway, that didn't work.

Anyone know if a mixed environment is possible on a farallon (proxim) broadband router?

If not, it looks like the apply now trick may be the one to use.

 

[mnkeybsness]

...your problem is the dhcp range...
it should be .100 to .199 the range should not differ unless you are running a huge network.

 

[Daveman Deluxe]

I expect that the DHCP range is linked to the range of allowable IP addresses. Here's what you should do:

1. Set the DHCP range to be 192.168.0.1-.40

2. Set your computer's manual IP address within that range.

That ought to work.

 

[mnkeybsness]

Originally posted by Daveman Deluxe
I expect that the DHCP range is linked to the range of allowable IP addresses. Here's what you should do:

1. Set the DHCP range to be 192.168.0.1-.40

2. Set your computer's manual IP address within that range.

That ought to work.

don't do that...

a static IP address cannot be within the allowed dhcp zone