[SYMBOL] [A] [B] [C] [D] [E] [F] [G] [H] [I] [J] [K] [L] [M] [N] [O] [P] [Q] [R] [S] [T] [U] [V] [W] [X] [Z] b class  b delivery agent flag  B line (qf file)  backslash (\)     in header fields      in rules  bad ruleset definition error message  base64 messages  batching rule testing  Bcc: header line  Berkeley vendor specification  bestmx database type  bestmx_is_local feature  BIND     obtaining via FTP      resource on  2nd  [See also DNS] bitdomain feature  BITNET addresses  BITNET_RELAY m4 macro  BITNET_RELAY mc macro  BITNET_SITECONFIG mc macro  blacklist_recipients feature  BlankSub option  blind carbon copy (Bcc)  body of message      B line (qf file)      in queue  2nd  BODY parameter (ESMTP)  2nd  bodytype= equate (syslog output)  bogus qf files  Boolean-type arguments  bouncing messages  2nd      down sites and      from retired accounts      mailing lists and  2nd      saved in qf file      to postmaster  2nd  braces { }  2nd  BROKEN_ANSI_LIBRARY compile-time macro  BROKEN_RES_SEARCH compile-time macro  BSD4_3 and BSD4_4 compile-time macros  btree database type  buffer, tokenization and  [See workspace] bugs  2nd      NIS and vfork  Build script  Build, top level version  building     alias database  2nd      sendmail  bulk precedence