PDA

View Full Version : Manually Assigning IP Addresses to Computers on LAN


Digital_Guy
11-11-2005, 08:29 PM
I'm guessing there is a way to do this ... I have 2 computers on an AirPort network in my house. One is a PowerBook G3 500 Mhz., and the other is an iMac G4 800 Mhz.. Both have 10.4.3. The AirPort's local IP is always 10.0.1.1. The problem I am having, perhaps it's not really a problem, but a situation, is that sometimes after restarting the AirPort and both machines, the PowerBook will take the local IP address of 10.0.1.2, and the iMac will take the local IP address of 10.0.1.3. Sometimes, they will switch, the PowerBook taking 10.0.1.3, and the iMac taking 10.0.1.2. What I want is for the PowerBook to always have the local IP address of 10.0.1.2, and the iMac to always have the IP address of 10.0.1.3. The only way I am able to achieve this configuration now is to shut down the entire network completely, and then turn the items on in the order that I want their local IP addresses to be (turning on the PowerBook and introducing it to the network before the iMac will give the PowerBook the local IP address of 10.0.1.2, and then the iMac will take the local IP address of 10.0.1.3). I have several dozen aliases on both machines that are links to items on the other machine, and the bulk of them requires that the PowerBook be located at 10.0.1.2, and the iMac to be at 10.0.1.3. The question is, is if it is possible to manually assign the PowerBook to 10.0.1.2 and the iMac to 10.0.1.3. If anyone knows if there is a manual workaround to achieve what I am doing now (restarting the network), I would appreciate a reply, along with some instructions on how to manually assign the IP addresses, on the local machines. In advance, thank you.

-D.G.

chabig
11-11-2005, 08:32 PM
This is easy. Just give each machine the IP address you want. Then go to Airport Admin utility and tell the base station not to assign IP addresses.

Chris

Digital_Guy
11-11-2005, 11:01 PM
Originally posted by Digital_Guy:
I would appreciate a reply, along with some instructions ..

Ummm ... ok. Thank you for telling me "yes". I was also looking for some instructions?

-D.G.

trevor
11-12-2005, 12:13 AM
Just give each machine the IP address you want.
Open System Preferences on the machine in question. Click Network. Click Airport. Go to the TCP/IP tab. Set "Configure IPv4" to Manually.
Type the IP address that you want for that machine: 10.0.1.2 or 10.0.1.3.
Set Subnet Mask to 255.255.255.0.
Set Router to 10.0.1.1.
Click "Apply Now".

Do the same for the other Mac (except of course with the other IP address).

Then go to Airport Admin utility and tell the base station not to assign IP addresses.

I don't have an Airport Base Station, so I can't check how you'd do this in Airport Admin Utility, but you must select your Base Station, then somewhere there's a popup menu where you choose to turn off DHCP.

Trevor

chabig
11-12-2005, 09:15 AM
Thanks for picking this this up Trevor...

Then go to Airport Admin utility and tell the base station not to assign IP addresses.
Open Airport Adming Utility. Your base station should show up. Select it and click on the Configure toolbar button (or double-click on the base station). In the resulting window, click on the Network tab. Uncheck "Distribute IP Addresses".

Chris

zeb
11-12-2005, 10:00 AM
Uncheck "Distribute IP Addresses"
Just out of curiosity, wouldn't this require that any other computer that gets introduced to this network (i.e. a friends laptop) be set to an IP address manually as well? If so, is there a way to have the Airport distribute IP addresses to all computers that don't already have a manually assigned IP?

chabig
11-12-2005, 10:34 AM
Just out of curiosity, wouldn't this require that any other computer that gets introduced to this network (i.e. a friends laptop) be set to an IP address manually as well?Yes.
If so, is there a way to have the Airport distribute IP addresses to all computers that don't already have a manually assigned IP?Yes. You can set the base station to limit the range of ip addresses it gives out. Say you limit the range from 10.0.1.2 to 10.0.1.99. Then I would assign manual IP address of 10.0.1.100 and 10.0.1.101 to the 2 computers.

And even simpler, just leave the base station alone and assign the two IP addresses to the computers. The base station doesn't care. If the computers don't ask for IP addresses the base station won't try to give them one, but the network will still work.

Chris

zeb
11-12-2005, 12:57 PM
And even simpler, just leave the base station alone and assign the two IP addresses to the computers. The base station doesn't care. If the computers don't ask for IP addresses the base station won't try to give them one, but the network will still work.I tried that. In that case, my computer with the manually assigned IP isn't able to connect to the network. See this thread, post #6 (http://forums.macosxhints.com/showthread.php?t=47230) for details. When I try your other suggestion to specify the range of IP's, I no longer get the option to use Port Mapping.

(Digital_Guy - I don't mean to high-jack your thread - but I do think this is relevant.)

trevor
11-12-2005, 01:25 PM
Zeb, I'm not completely understanding what your issue is, but can you verify "my computer with the manually assigned IP isn't able to connect to the network", because I suspect you might be jumping to that conclusion too quickly. What I think more likely is that "my computer with the manually assigned IP isn't getting DNS".

Here's how to verify it. First, make sure that you are apparently connected to your Airport network with a manually assigned IP. Open up Network Utility from /Applications/Utilities. In the Info tab, make sure it is set to the network interface you are using. If you're on Airport, that will most likely be "en1".

Now, go to the ping tab, and where it says "please enter the network address to ping" enter the following:
66.94.234.13

This is Yahoo!'s IP address. Click the Ping button. Do you get results that look similar to
Ping has started ...

PING 216.239.57.99 (216.239.57.99): 56 data bytes
64 bytes from 216.239.57.99: icmp_seq=0 ttl=240 time=86.173 ms
64 bytes from 216.239.57.99: icmp_seq=1 ttl=240 time=73.091 ms
64 bytes from 216.239.57.99: icmp_seq=2 ttl=240 time=72.882 ms

--- 216.239.57.99 ping statistics ---
3 packets transmitted, 3 packets received, 0% packet loss
round-trip min/avg/max = 72.882/77.382/86.173 ms

Or do you get results similar to
Ping has started ...

PING 216.239.57.99 (216.239.57.99): 56 data bytes

--- 216.239.57.99 ping statistics ---
3 packets transmitted, 0 packets received, 100% packet loss

If you get the results of the first example, you are connected to the internet, you just may not have DNS. Let us know and we'll explain how to fix that.

You can also plug yahoo.com in and verify that you can or can't get DNS.

Trevor

zeb
11-12-2005, 01:46 PM
Thanks Trevor. You're right. I can ping the IP (I get results like the first example you posted), but I cannot resolve the yahoo.com DNS

(BTW, I love that line from Office Space)

trevor
11-12-2005, 02:37 PM
OK, good. Then the fix is easy. System Preferences > Network > Airport > TCP/IP tab > enter your DNS servers in the blank provided. Best is to enter the DNS servers provided by your ISP (if you don't know them, ask your ISP). Otherwise, you can try 1. to enter your router's IP there, or 2. to use public DNS servers. Do a websearch and you can find a good number of them.

Trevor