Can't access internet after changing IP addr to static from DHCP

Question

Level 3

912 points

Can't access internet after changing IP addr to static from DHCP

I've got 2 macs in my network. One is set to a static ip address (it still runs Tiger). On my brand new mac, I changed it from using DHCP to a static ip. After that change, I could no longer access anything on the internet. I rebooted, same issue. I checked the router (UVerse residential gateway) and it showed my machine with the new static ip I set. Changed it back to use DHCP, and it started working again. I want to use a static ip so that I can talk to it from my other mac. For some reason, if the ip changes, I can no longer use the network alias to connect. Like I said, the other mac uses a static ip xxx.xxx.xx.2, I set the new mac to xxx.xxx.xx.3. Should be a no brainer...

Any ideas?

Thanks

iMac 3.06 GHz Intel Core i3, Mac OS X (10.6.5), - 20" iMac G5 (iSight) - 17" iMac G4 FP - 2 iPods - iPhone 3g 16GB

Posted on Dec 10, 2010 10:18 PM

Reply

Answer 1

Best reply

nachdenki

Level 3

649 points

Dec 11, 2010 3:28 AM in response to Alfredo Jahn

well, there are several things to consider here

1) your router might be set in a way that it hands out the .3 IP via DHCP, so another machine on the network might be using the .3 address already

2) do you have another device set up to use .3?

3) do you have set your subnetmask, routing and DNS information? those are important. subnetmask should be 255.255.255.0 and routing and DNS is the IP of your router in most cases

4) your static IP should start with either 192. or 10., is that the case?

5) if all of that doesn't help, can you access your router with the static IP (entering its IP in the browser URL field)?

edit: also, OS X has a little annoying bug where it sometimes deletes your DNS info when you switch from DHCP to manual IP. after you are done, click apply in the network settings dialog, go back to the system preferences main dialog, back into network, click advanced, switch to the DNS tab and make sure your DNS IP is present in the DNS-Servers list. if not, add it and apply the changes.

Reply

Answer 2

Alfredo Jahn Author

Level 3

912 points

Dec 11, 2010 5:20 AM in response to nachdenki

Thanks for your response.

I checked my router and here are the ip addresses that it "sees" on the network:

192.168.1.64
192.168.1.67
192.168.1.66
192.168.1.148
192.168.1.2 static
192.168.1.69
192.168.1.70

Note that all IPs are given out using DHCP, except the .2 which is my other iMac that is using a static ip and works just great. My network consists of 2 TVs, an iPhone, 3 computers and a Wii. I could care less if the TVs, Will an iPhone get a dynami ip, but I would like my computers to have static ips. I'm not sure if the submask has anything to do with it, since i already have one using 192.168.1.2, so using 192.168.1.3 should work, don't you think?

Any other thoughts?

On last, important, question. Don't macs figure out what is on the network and show them in the network as machine names? eg. "Joe's iMac"? If you reboot, and get a different ip, shouldn't the macs handle that? That is my real problem, and why I am trying to use static ip addresses. When I try to access one mac from the other, it tells me the "alias" is wrong.

Thanks

Reply

Answer 3

BobHarris

Level 9

53,255 points

Dec 11, 2010 5:23 AM in response to Alfredo Jahn

Most routers have a range of IP addresses the hand out for DHCP. I like to either change the router so it uses addresses above the fixed IP addresses I want to use, or I pick fixed IP addresses above the router's DHCP range. It avoids IP address collisions.

Another test is to use the networking utility to 'ping' a known Internet IP address. If that works, it likely your DNS setup that needs attention.

Reply

Answer 4

etresoft

Level 8

46,530 points

Dec 11, 2010 5:33 AM in response to Alfredo Jahn

Alfredo Jahn wrote:
One is set to a static ip address (it still runs Tiger).

Tiger can do DHCP without any problem.

Reply

Answer 5

Alfredo Jahn Author

Level 3

912 points

Dec 11, 2010 5:54 AM in response to etresoft

Thanks to everyone for your suggestions...

I've got it working now!

Instead of choosing "Manual" for the "Configure IPv4" setting, I tried "Using DHCP with manual address". That retained my submask, router and DNS Server settings that were used with the "Using DHCP" setting. Seems to be working. I now have a static ip.

Now my next trick is to figure out how to connect from my other mac.

Thanks

Reply

Answer 6

BobHarris

Level 9

53,255 points

Dec 11, 2010 6:57 AM in response to Alfredo Jahn

Now my next trick is to figure out how to connect from my other mac.

If you enter an easy to type System Preferences -> Sharing -> Computer Name, then you should be able to reference each computer (while at home) using "computername.local". This is the Bonjour service at work.

File sharing would be:
Finder -> Go -> Connect to server -> afp://computername.local

Screen Sharing would be:
Finder -> Go -> Connect to server -> vnc://computername.local

If you are using ssh/scp/sftp commands from a Terminal session, it would be:
ssh username@computername.local
scp file username@computername.local:/destination/path
sftp username@computername.local

And you can always just use your fixed IP address.

And generally, if the other Mac is advertising file sharing or screen sharing services via Bonjour, the other system tends to show up in the Finder sidebar (or at least it does on Leopard and Snow Leopard; too long since I used Tiger).

I've found that WakeOnLan does a very good job of discovering all the active devices on your home network, even if you do not want to wake any systems up
<http://www.macupdate.com/info.php/id/15779/wakeonlan>

Reply

Answer 7

Dec 11, 2010 6:23 PM in response to Alfredo Jahn

depends on how you created the alias. Or should I say, how you connected to the server before you created the alias. If you used the IP address to connect, that is what the alias stores.

Alfredo Jahn wrote:
If you reboot, and get a different ip, shouldn't the macs handle that? That is my real problem, and why I am trying to use static ip addresses. When I try to access one mac from the other, it tells me the "alias" is wrong.

Thanks

Reply