Automated configuration of TCP/IP with DHCP

The TCP/IP suite has various protocols that must be carefully configured so that networked devices operate efficiently. Setting values by hand is time-consuming and error-prone; moreover, several trends are adding to the need for automated parameter configuration and administration. The Dynamic Host Configuration Protocol, accepted as a proposed standard by the Internet Engineering Task Force, offers a way to automatically configure network devices that use TCP/IP. These devices use DHCP to locate and contact servers, which return the appropriate configuration information as data. The DHCP servers act as agents for network administrators and automate the process of network address allocation and parameter configuration. Addresses can be assigned and individual addresses can be reassigned to new DHCP clients without explicit intervention by a network administrator. The IETF's Dynamic Host Configuration (DHC) working group is now at work adding new features to DHCP. The author describes the group's work on DHCP in detail, outlines the management of a DHCP service, and discusses new DHCP features, including the version being developed for IPv6     

Dexamethasone enhances colonization of soft agar by tumorigenic mouse lung-derived cell lines

When cultured on plastic, tumorigenic mouse lung-derived cell lines exhibit different proliferative responses to glucocorticoids; some lines are inhibited while others are stimulated or unaffected. In contrast to the variable dexamethasone responses when cells are cultured on plastic, soft agar colonization by each of these cell lines is enhanced by dexamethasone. Enhanced soft agar growth is unlikely to result from expression of a mutant glucocorticoid receptor, since dexamethasone also enhanced colony formation in two cell lines that stably express a transfected normal glucocorticoid receptor gene. Thus, cell attachment influences the effect of glucocorticoids on cell cycle progression.