We have 5 Mac Pros in my office, all running 10.6.8, today for some reason NONE of them had internet access, all the PCs in the office ran fine. It seems that for some reason, DHCP was giving us the wrong IP address. 192.168.1.x instead of what our internal server uses 10.1.1.x, I have no idea why this would only effect macs. And the kicker is, we plugged in an old iMac running on 10.4 and it was assigned the correct IP address. We were able to manually reset the IP addresses, but why would this be happening, I am totally stumped.
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OS X 10.6 IP Issues
- Thread starter cbt3
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Well I would be checking for a second DHCP server on your network running on the 192.168 subnet that is the only way they should get that address range. If it was IP screw up on the machines they would most likely get one of them 169 self assigned address.
Indeed. Check for wireless access points which can sometimes be routers configured differently, airports for example as wireless LAN extenders when some moron presses the reset hole. In network configuration reset one of the Mac Pro's to automatic ip to get the ip off the miscreant device then try to log onto it using the gateway and/or server address supplied using a web browser. Usually 192.168.X. Last digit usually either 1 or 254. The x is cos you never supplied the third part of the IP address.
If you can't log on you can at least get a clue. If you can obtain the hex MAC address of the dhcp server you can usually find out which manufacturer it is.
Open terminal
Type ping 192.168.xxx.xxx enter
type arp -a enter
That gives the MAC address
Then look it up here:
http://www.coffer.com/mac_find/
If it's an Apple manufacturer MAC address run airport utility on the tower you changed earlier and check whether one of them is in router and not bridge mode as it should be, getting its ip from the usual 10.1.1.xxx dhcp server.
I've just done myself out of some money here
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To OP :
I have a question : why are your 5 Mac pro in DHCP ?
Why don't they have static IP addresses ??
I have a question : why are your 5 Mac pro in DHCP ?
Why don't they have static IP addresses ??
More like why doesn't the dhcp server have them reserved! I smell an airport. If it's closer to the computers than the server is it will hijack their ip allocation and it has a default 192.168 ip and no web interface in router mode..
Do people really run without DHCP these days? Your basic $40 router does DHCP. And if you want the status addresses, just use static DHCP.
I do know.
But OP said :
"DHCP was giving us the wrong IP address. 192.168.1.x instead of what our internal server uses 10.1.1.x".
If the Mac Pros had 10.1.1.x static IP addresses, they would never had received 192.168.1.x "wrong" addresses.
I don't see any reason for 5 Mac Pros in an office to be in DHCP.
If I was the IT guy there, I would set them with static IP addresses.
I would be giving the person who pressed the reset on the airport/access point a severe telling off first. I certainly wouldn't say I'd set them as static cos we don't have a clue how their network is setup, we're blind! For example if they connect to active directory the server may want to issue the IP address..
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Indeed. Check for wireless access points which can sometimes be routers configured differently, airports for example as wireless LAN extenders when some moron presses the reset hole. In network configuration reset one of the Mac Pro's to automatic ip to get the ip off the miscreant device then try to log onto it using the gateway and/or server address supplied using a web browser. Usually 192.168.X. Last digit usually either 1 or 254. The x is cos you never supplied the third part of the IP address.
If you can't log on you can at least get a clue. If you can obtain the hex MAC address of the dhcp server you can usually find out which manufacturer it is.
Open terminal
Type ping 192.168.xxx.xxx enter
type arp -a enter
That gives the MAC address
Then look it up here:
http://www.coffer.com/mac_find/
If it's an Apple manufacturer MAC address run airport utility on the tower you changed earlier and check whether one of them is in router and not bridge mode as it should be, getting its ip from the usual 10.1.1.xxx dhcp server.
I've just done myself out of some money here
Like I said, we were able to get connected by using manual setup.
Also note, we have been connected with no issues since they upgraded the server to one that uses 10.1.1.x for over a year or two without issue.
I forgot to mention, when we had tried connecting before, we had gotten sent to a webpage with this message {see attachment}:
However, my computer is a early 2008 model and does not have airport, the others should have it turned off.
When I connect through DHCP, I can ping the router which is 192.168.1.240 for some reason, and when I enter arp -a in the terminal I get
? (169.254.1.0) at (incomplete) on en0 [ethernet]
? (192.168.1.5) at f0:4d:a2:26:1f:87 on en0 ifscope [ethernet]
? (192.168.1.240) at f8:78:8c:1:64:42 on en0 ifscope [ethernet]
? (192.168.1.255) at ff:ff:ff:ff:ff:ff on en0 ifscope [ethernet]
It's always run on DHCP with automatic IP, why isn't it reserved, idk, my IT dept is not the most inept or I wouldn't be looking for help here.
We never did anything to airport on our computers, we left yesterday with everything working, this morning, it wasn't.
If I try to enter DHCP with manual address, that doesn't work either, even with a 10.1.1.x IP address. I have to do full manual.
As of right now, we are all on manual, and have static IP addresses, all manual, should we just leave it as is? And not worry about trying to get the IT department to fix the problem that just came up out of nowhere?
That wireless repeater/extender is the culprit, it's reset itself somehow and started acting like its a router, probably not repeating your wifi signal on anymore so you may have wireless dead spots. It needs reconfiguring by the it dept ideally when they are next in. Best check it hasn't hijacked anything else connected like printers and other devices, they can be a bit more of a pain to change the ip than a mac. Best write down every static ip you have set for reference and also for the windows boxes!
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but we are NOT using wireless! that is the weird thing... :-\
also why would it only be acting like a router for these 5 macs? and it isn't like we are on a separate port or anything, by my desk i have a PC and a printer hooked up to a switch with my mac that had no issues.
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If you eliminate the impossible....That extender has to be connected to your LAN somewhere as that model does have a wired connection!
http://www.ampedwireless.com/products/sr300.html