Mac OS X 10.7.x Network Configuration:
TCP/IP Configuration for Ethernet

This document is part of of Mac OS X 10.7.x Network Configuration, and describes how to configure TCP/IP on a Mac OS X 10.7.x system connected to the campus network with OIT Ethernet wiring.

The Mac OS X 10.7.x Network Configuration documentation covers most common cases. It directs you to this document for a few uncommon situations that require detailed instructions. We assume you have reached this point by following the instructions in that earlier document.

Choosing to Use DHCP

The instructions below include different steps depending on whether you choose to use DHCP, BootP, or manual configuration. DHCP allows TCP/IP to automatically determine most network parameters. (So does BootP, an older service, but it provides less information to your Mac.)

We strongly recommend you choose to use DHCP. Some facilties are only available if you use DHCP.

If you choose to use manual configuration (not DHCP nor BootP), then before proceeding you must:

1. Determine the IP address assigned to the Mac's network interface. If you don't know how, see What IP Address is Assigned to My Mac's Network Interface?.

2. Verify that this IP address is an OIT Static IP Address.

   You may use the Categorize IP Address tool to determine whether an IP address you enter is an OIT Static IP Address.

   If your Mac's network interface does not have an OIT Static IP Address assigned to it, you must not manually configure that network interface. You must use DHCP instead.

3. Determine the default IP router and network mask appropriate for that OIT Static IP Address, by consulting Default IP Routers, Network Masks, and Broadcast Addresses. (Note that to look up these values, you will first need to know your network interface's assigned's OIT Static IP Address.)

Configuring TCP/IP

1. The System Preferences application should already be open, with the Network pane selected.

   The location you wish to configure should appear in the Network pane's Location pop-up menu.

2. In the list of network interfaces displayed along the left side of the Network pane, select the interface you wish to configure.

3. Click the Advanced... button near the lower-right corner of the display of basic configuration items. This displays a sheet with advanced configuration items for the selected interface, organized under a series of tabs.

4. If you do use DHCP service (normally recommended), follow these steps:
   1. Click the TCP/IP tab. Configure TCP/IP as follows:
      1. In the Configure IPv4 pop-up menu, select Using DHCP.

      2. Make sure the DHCP Client ID field is entirely empty. It should not contain even spaces.

      3. In the Configure IPv6 pop-up menu, select Off if that choice appears. Otherwise, select Link-local only.

   2. Click the DNS tab. Configure DNS as follows:
      1. Make sure that the DNS Servers list is empty or contains only IP addresses that are in greyed-out type. (Addresses that are greyed-out are ones the device has learned via non-manual configuration, such as DHCP or BootP. These are fine.) If any IP address appears in this list in normal type (not greyed-out), remove that IP address by selecting it and then clicking the - (minus) button below the list.

      2. Make sure that the Search Domains list is empty or contains only DNS domains that are in greyed-out type. (DNS domains that are greyed-out are ones the device has learned via non-manual configuration, such as DHCP or BootP. These are fine.) If any DNS domain appears in this list in normal type (not greyed-out), remove that DNS domain by selecting it and then clicking the - (minus) button below the list.

   3. Click the WINS tab. Configure WINS as follows:
      1. A NetBIOS Name may already be set. If the computer has obtained an IP address, and was able to use DNS to resolve that IP address to a DNS hostname, it uses the first component of the DNS hostname as the NetBIOS Name. Otherwise, if a Computer Name is set in the Sharing pane of System Preferences, it may use that.

      2. Make sure that the WINS Servers list is empty or contains only IP addresses that are in greyed-out type. (Addresses that are greyed-out are ones the device has learned via non-manual configuration, such as DHCP or BootP. These are fine.) If any IP address appears in this list in normal type (not greyed-out), remove that IP address by selecting it and then clicking the - (minus) button below the list.

5. If you use BootP service instead of DHCP (not usually recommended), follow these steps:
   1. Click the TCP/IP tab. Configure TCP/IP as follows:
      1. In the Configure IPv4 pop-up menu, select Using BootP.

      2. In the Configure IPv6 pop-up menu, select Off if that choice appears. Otherwise, select Link-local only.

   2. Click the DNS tab. Configure DNS as follows:
      1. Make sure that the DNS Servers list is empty or contains only IP addresses that are in greyed-out type. (Addresses that are greyed-out are ones the device has learned via non-manual configuration, such as DHCP or BootP. These are fine.) If any IP address appears in this list in normal type (not greyed-out), remove that IP address by selecting it and then clicking the - (minus) button below the list.

      2. Make sure that the Search Domains list is empty or contains only DNS domains that are in greyed-out type. (DNS domains that are greyed-out are ones the device has learned via non-manual configuration, such as DHCP or BootP. These are fine.) If any DNS domain appears in this list in normal type (not greyed-out), remove that DNS domain by selecting it and then clicking the - (minus) button below the list.

   3. Click the WINS tab. Configure WINS as follows:
      1. A NetBIOS Name may already be set. If the computer has obtained an IP address, and was able to use DNS to resolve that IP address to a DNS hostname, it uses the first component of the DNS hostname as the NetBIOS Name. Otherwise, if a Computer Name is set in the Sharing pane of System Preferences, it may use that.

      2. In the WINS Servers list, enter the following items, one per line:

               128.112.128.95
               128.112.128.97
         

         In order to enter each line in the list, you will need to first click the + (plus) button button below the list.

6. If you use manual configuration instead of DHCP or BootP service (not normally recommended except in unusual circumstances), follow these steps:
   1. Click the TCP/IP tab. Configure TCP/IP as follows:
      1. In the Configure IPv4 pop-up menu, select Manually.

         (Never select Using DHCP with manual IP address.)

      2. In the IPv4 Address field, enter the OIT Static IP Address assigned to the network interface you are configuring.

         Before entering it, be absolutely sure you are entering your network interface's assigned OIT Static IP Address, not the address of your default IP router, another computer's IP address, or any IP address which the Categorize IP Address tool indicates is anything other than an OIT Static IP Address.

      3. In the Subnet Mask field, enter the subnet mask (a.k.a. "network mask", or "netmask") appropriate for your IP address. This will be a value like 255.255.252.0 (your numbers may be different).

      4. In the Router field, enter the default IP router (a.k.a. "gateway") address appropriate for your IP address.

      5. In the Configure IPv6 pop-up menu, select Off if that choice appears. Otherwise, select Link-local only.

   2. Click the DNS tab. Configure DNS as follows:
      1. In the DNS Servers list, enter any three of the following four address, one per line (you may enter them in any order):

               128.112.133.220
               128.112.129.32
               128.112.129.111
               128.112.128.1
         

         In order to enter each line, you will need to first click the + (plus) button button below the list.

      2. Determine your default DNS domain name. This is your Mac's Internet hostname, with the first word (up through the first period) removed. If your Mac is associated with a Dormnet subscription, your default DNS domain name is student.princeton.edu. Otherwise, your default DNS domain name is usually princeton.edu. (A few departments have a different default DNS domain name, e.g. basketweaving.princeton.edu.)

         If your default DNS domain name is princeton.edu, etner (only) princeton.edu in the Search Domains list. The list should contain no other entries.

         Otherwise, if your Mac's default DNS domain name is not princeton.edu, enter the default DNS domain name as the first entry in the Search Domains list. Enter princeton.edu as the second entry in the list. The order of the entries is important. For example, if your Mac's default DNS domain name is basketweaving.princeton.edu, enter basketweaving.princeton.edu as the first entry in the list, and princeton.edu as the second entry in the list.

         (If there are multiple DNS subdomains between your Mac's default DNS domain name and princeton.edu, enter each name in the list, one per line, starting with the most-specific domain name. For example, if your Mac's hostname is foo.bar.baz.princeton.edu, your default DNS domain name is bar.baz.princeton.edu, so enter bar.baz.princeton.edu, baz.princeton.edu, and princeton.edu, in that order.

         In order to enter each line in the list, you will need to first click the + (plus) button button below the list.

   3. Click the WINS tab. Configure WINS as follows:
      1. A NetBIOS Name may already be set. If the computer was able to use DNS to resolve the IP address you entered above, it uses the first component of the DNS hostname as the NetBIOS Name. Otherwise, if a Computer Name is set in the Sharing pane of System Preferences, it may use that.

      2. In the WINS Servers list, enter the following items, one per line:

               128.112.128.95
               128.112.128.97
         

         In order to enter each line in the list, you will need to first click the + (plus) button button below the list.

7. Click the OK button in the lower right corner of the network port's advanced configuration sheet to dismiss the sheet and return to the basic settings for this network port.

8. Click the Apply  button in the lower-right corner of the Network pane to save the configuration for this network port.