DHCP requirements

Rational® ClearCase® is compatible with most DHCP configurations, although it has a few special requirements that you must be aware of.

The Dynamic Host Configuration Protocol (DHCP) is an Internet standard protocol that allows a host to obtain a temporary, dynamically assigned IP address from a DHCP server. DHCP is widely implemented on Windows® computers, and also on some computers running Linux® or the UNIX® system.

Rational ClearCase hosts cache the IP addresses of other Rational ClearCase hosts (usually servers) that they access. If a cached address becomes incorrect because the remote host has been assigned a new IP address by DHCP, Rational ClearCase applications that rely on the cached address may fail. Because Rational ClearCase server hosts are usually running and connected to the network, they are likely to keep the IP addresses that their clients have cached, which makes these sorts of failures unlikely. If DHCP is in use at your site, the following guidelines should be observed to further minimize the chance of such failures:
  • If possible, assign fixed IP addresses to Rational ClearCase server hosts.
  • Set the DHCP lease time (the length of time for which a host can use a DHCP-assigned address) to be at least twice as long as any Rational ClearCase host is likely to be down or off the network. The DHCP lease time is typically established by the DHCP server.
  • Do not configure Rational ClearCase hosts to obtain a new DHCP address when they restart.

Feedback