Debugging check_rcpt in sendmail 8.8

1. e-mail from intern to extern:

   sendmail -bt -d21.4
   > .D{client_addr}134.245.15.1
   > check_rcpt <a@aol.com>
   rewrite: ruleset 190   input: < a @ aol . com >
   rewrite: RHS $&client_addr => "134.245.15.1"
   rewritten as: 134 . 245 . 15 . 1 $| < a @ aol . com >
   rewritten as: ok
   rewrite: ruleset 190 returns: ok
   

2. e-mail from extern to intern,

   sendmail -bt -d21.4
   > .D{client_addr}1.2.3.4
   > check_rcpt <a@informatik.uni-kiel.de>
   rewrite: ruleset 190   input: < a @ informatik . uni-kiel . de >
   rewrite: RHS $&client_addr => "1.2.3.4"
   rewritten as: 1 . 2 . 3 . 4 $| < a @ informatik . uni-kiel . de >
   -----callsubr 3 (3)
   rewrite: ruleset   3   input: < a @ informatik . uni-kiel . de >
   rewritten as: < a @ informatik . uni-kiel . de > < @ >
   rewritten as: < a @ informatik . uni-kiel . de >
   rewritten as: < < a @ informatik . uni-kiel . de > >
   rewritten as: < a @ informatik . uni-kiel . de > >
   rewritten as: < a @ informatik . uni-kiel . de >
   rewritten as: a @ informatik . uni-kiel . de
   rewritten as: a < @ informatik . uni-kiel . de >
   -----callsubr 96 (96)
   rewrite: ruleset  96   input: a < @ informatik . uni-kiel . de >
   rewritten as: a < @ informatik . uni-kiel . de . >
   rewritten as: a < @ informatik . uni-kiel . de . . >
   rewritten as: a < @ informatik . uni-kiel . de . >
   rewrite: ruleset  96 returns: a < @ informatik . uni-kiel . de . >
   rewritten as: a < @ informatik . uni-kiel . de . >
   rewrite: ruleset   3 returns: a < @ informatik . uni-kiel . de . >
   rewritten as: a < @ informatik . uni-kiel . de . >
   -----callsubr 3 (3)
   rewrite: ruleset   3   input: a
   rewritten as: a < @ >
   rewritten as: a
   rewritten as: < a >
   rewritten as: a
   -----callsubr 96 (96)
   rewrite: ruleset  96   input: a
   rewrite: ruleset  96 returns: a
   rewritten as: a
   rewrite: ruleset   3 returns: a
   rewritten as: a
   rewrite: ruleset 190 returns: a
   

3. e-mail from extern to extern.

   sendmail -bt -d21.4
   > .D{client_addr}1.2.3.4
   > check_rcpt <a@aol.com>
   rewrite: ruleset 190   input: < a @ aol . com >
   rewrite: RHS $&client_addr => "1.2.3.4"
   rewritten as: 1 . 2 . 3 . 4 $| < a @ aol . com >
   -----callsubr 3 (3)
   rewrite: ruleset   3   input: < a @ aol . com >
   rewritten as: < a @ aol . com > < @ >
   rewritten as: < a @ aol . com >
   rewritten as: < < a @ aol . com > >
   rewritten as: < a @ aol . com > >
   rewritten as: < a @ aol . com >
   rewritten as: a @ aol . com
   rewritten as: a < @ aol . com >
   -----callsubr 96 (96)
   rewrite: ruleset  96   input: a < @ aol . com >
   rewritten as: a < @ aol . com . >
   rewritten as: a < @ aol . com . . >
   rewritten as: a < @ aol . com . >
   rewrite: ruleset  96 returns: a < @ aol . com . >
   rewritten as: a < @ aol . com . >
   rewrite: ruleset   3 returns: a < @ aol . com . >
   rewritten as: a < @ aol . com . >
   rewritten as: $# error $@ 5 . 7 . 1 $: 550 we do not relay
   rewrite: ruleset 190 returns: $# error $@ 5 . 7 . 1 $: 550 we do not relay