Mac OS: How to release and renew a DHCP lease

  • Last Modified: July 21, 2008
  • Article: TS1920
  • Old Article: 106879

Symptoms

1. You can no longer connect to the Internet.

2. You may receive a self-assigned IP address that starts with a 169, rather than one that is valid for your Internet service provider's network.

Note: Addresses in the self-assigned range (169.x.x.x) are usually not routed for traffic on the public Internet. A 169 address typically indicates that your DHCP server is not assigning you a valid IP address or that you cannot connect to the network to receive the address. Though it is a very rare practice, beware that your Internet service provider or institutional network could choose to assign these addresses and route them within their private network. If you can connect to the Internet with an address that begins in 169, that could be normal for your network. If this is in question, contact your network administrator or ISP for verification of the expected IP address range.

Products Affected

Mac OS

Resolution

If you are experiencing this issue on a network that uses an AirPort Base Station or third-party router, stop here and go to technical document 106858, "AirPort: Troubleshooting Outline". Apple does not provide specific instruction for third-party routers, but most of the same troubleshooting logic applies.

Mac OS X instructions

I. Force reconfiguration of IP settings

Either restart your computer or follow these steps:

    1. Close any open Internet applications (such as Web browsers and email). Be sure to save any changes to any open documents.
    2. Choose System Preferences from the Apple menu.
    3. Choose Network from the View menu.
    4. Choose Active Network Ports from the Show menu.
    5. Deselect the "on" checkbox for port you use to connect to the Internet (such as Built-in Ethernet or AirPort).
    6. Click Apply Now.
    7. Reselect the checkbox for the port.
    8. Click Apply Now.
    9. Open a Web browser, and attempt to connect.


If your issue is resolved, you may stop here.

II. Reset DSL or cable modem

If you use a DSL or cable modem and do not succeed on your first attempt, these additional steps address a potential scenario in which the issue is caused by hardware access provisioning, an access control method used by some Internet service providers. Provisioning may cause the symptom when you are switching your connection between different computers, devices, or different Ethernet ports.

    1. Press the reset button on the DSL or cable modem, if it has one.
    2. Unplug the DSL or cable modem from its power supply.
    Note: Some DSL or cablem modems contain internal batteries which can cause the modem to retain power even though the plug has been removed. Make sure the lights on the modem go out when removing power. If they do not, check for internal batteries or a battery backup system.
    3. If you have more than one Ethernet-capable computer or device connected to a network, temporarily disconnect all but the one you intend to obtain the DHCP lease. The prevents another device from taking the DHCP lease before the intended computer does.
    4. Plug the DSL or cable modem back in after one minute has elapsed.
    5. Repeat Section I.


Mac OS 9 instructions

I. Force reconfiguration of IP settings

Either restart your computer or follow these steps:

    1. Close any open Internet applications (such as Web browsers and email). Be sure to save any changes to any open documents.
    2. Open the TCP/IP control panel.
    3. Choose User Mode from the Edit menu.
    4. Click the radio button for Advanced.
    5. Click OK.
    6. Click Options.
    7. Click the radio button for Inactive.
    8. Click OK.
    9. Close the TCP/IP control panel.
    10. When prompted, click Save.
    11. Open the TCP/IP control panel.
    12. When prompted, click Yes.
    13. Close the TCP/IP control panel.
    14. Open a Web browser, and attempt to connect.


If your issue is resolved, you may stop here.

II. Reset DSL or cable modem

If you use a DSL or cable modem and do not succeed on your first attempt, these additional steps address a potential scenario in which the issue is caused by hardware access provisioning, an access control method used by some Internet service providers. Provisioning may cause the symptom when you are switching your connection between different computers, devices, or different Ethernet ports.

    1. Press the reset button on the DSL or cable modem, if it has one.
    2. Unplug the DSL or cable modem from its power supply.
    Note: Some DSL or cablem modems contain internal batteries which can cause the modem to retain power even though the plug has been removed. Make sure the lights on the modem go out when removing power. If they do not, check for internal batteries or a battery backup system.
    3. If you have more than one Ethernet-capable computer or device connected to a network, temporarily disconnect all but the one you intend to obtain the DHCP lease. The prevents another device from taking the DHCP lease before the intended computer does.
    4. Plug the DSL or cable modem back in after one minute has elapsed.
    5. Repeat Section I.

Additional Information

106796: "Mac OS X: Internet and Network Topics (Getting Connected, Troubleshooting)"
106877: "Mac OS 9: Internet and Network Topics (Getting Connected, Troubleshooting)"
18237: "DHCP: What Is It?"

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