2.30. IpHead *global*
Implements the domain/IP session qualifiers so that only the first IpQuad dot-quads of the IP address are used to qualify the session ID. The default is 1. This is a slight compromise on security, but it allows non-cookie-accepting browsers, like AOL's V2.0, to use multiple proxy servers.
DomainTail is preferable unless one of your HTTP servers does not do host name lookups. Default is No, and DomainTail must be set to No for it to operate.