[exim] need help with NIS

We're trying to switch to using NIS tables
during SMTP authentication, but cant get
anything to work. We dont really understand
how one is supposed to use the nis lookup

We currently have things like:

fixed_plain:
  driver = plaintext
  public_name = PLAIN
  server_prompts = :
  server_condition = ${if crypteq{$3}\
    {${extract{1}{:}{${lookup{$2}lsearch{/etc/shadow}{$value}}}}\
    }{yes}{no}}

and would like to replace the search of /etc/shadow
with a nis{passwd} thing. What is the syntax?

{${extract{1}{:}{${lookup{$2}lsearch{nis{passwd}}{$value}}}}\

doesnt work, and neither does

{${extract{1}{:}{${lookup{$2}{nis{passwd}}{$value}}}}\

How do we extract a line from nis's passwd tables using a
userid as a keyword?

Thanks,
Terry

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