Mac OS 8.6: Computer Pauses Every Five Minutes On DHCP

It sometimes seems that my computer, which is running Mac OS 8.6, becomes unresponsive for about 25 seconds upon first IP activity and then every five minutes thereafter. It seems to occur under the following circumstances:
  • TCP/IP set to Connect via "Ethernet"
  • TCP/IP set to Configure via "Using DHCP Server"
  • Computer is on a network that does not have active DHCP services, or computer is not attached to an Ethernet network
When a DHCP server is not available and the computer is configured as above, the computer searches for a DHCP server until it times out in about 25 seconds. At this point, the computer will select a temporary IP address in the non-routable 169.254.x.x range. The computer will continue to look for a DHCP server every five minutes until a DHCP server is found. On this five minute interval, the computer becomes unresponsive for another 25 seconds or so.

This should not occur if your computer is on a TCP/IP network that provides IP addressing via DHCP. If it does occur, the server may be down or there may be a network issue. Consult your network administrator for further assistance.

Identification
If you are experiencing 'pauses' of about 25 seconds at five minute intervals, open the TCP/IP control panel. If TCP/IP is set to configure "Using DHCP Server" and the IP address is in the 169.254.x.x range, your computer is exhibiting the behavior described above.

Another cause of pausing on iMacs running Mac OS 8.6 is resolved by the iMac CD Update 1.0. Please refer to the following article for complete details on this specific issue: Article 58412: " iMac: How To Resolve Intermittent Pause During Usage".

Workarounds
If your computer is on a TCP/IP network that does not supply DHCP services, you should set TCP/IP to use an appropriate configuration method; for example, Configure Manually.

If your computer is temporarily not connected to a TCP/IP network that supplies DHCP services, make TCP/IP inactive or configure TCP/IP to connect using a different method; for example, Connect via AppleTalk (MacIP) or Connect via PPP.

In Mac OS 9 and later with Open Transport 2.6 and later, your computer will no longer pause when attempting to renew a DHCP lease.

Note: If you are unable to change the settings in the TCP/IP control panel, your network administrator may have locked the settings to prevent modification. Consult your network administrator if these settings are locked.

Published Date: Feb 20, 2012