Milter-greylist

> define(`confMAPDEF', `-DNEWDB')
> define(`conf_sendmail_ENVDEF', `-DSASL=2')
> define(`confINCDIRS', `-I/usr/local/include')
> define(`confLIBDIRS', `-L/usr/local/lib')
> define(`conf_sendmail_LIBS', `-lsasl2')
> APPENDDEF(`confENVDEF', `-DMILTER')
> APPENDDEF(`confLIBS', `-ldb')
> APPENDDEF(`conf_sendmail_ENVDEF', `-DNETINET6')
> APPENDDEF(`conf_libmilter_ENVDEF', `-DNETINET6')
> APPENDDEF(`conf_mail_local_ENVDEF', `-DQUEUE_ONLY')
> APPENDDEF(`conf_sendmail_ENVDEF', `-DSTARTTLS')
> APPENDDEF(`conf_sendmail_ENVDEF', `-D_FFR_TLS_O_T')
> APPENDDEF(`conf_sendmail_ENVDEF', `-D_FFR_TLS_1')
> APPENDDEF(`conf_sendmail_ENVDEF', `-D_FFR_TLS_TOREK')
> APPENDDEF(`conf_sendmail_LIBS', `-lssl -lcrypto')
> the Mimedefang milter works fine with IPv6; this should not work as 
> well if libmilter would not support IPv6...
I wonder if the problem is in one of the underlying shared libraries.
milter-greylist needs these libraries:
   NEEDED               libcurl.so.4
   NEEDED               libGeoIP.so.1
   NEEDED               libpthread.so.0
   NEEDED               libspf2.so.2
   NEEDED               libresolv.so.2
   NEEDED               libmilter.so.1.0
   NEEDED               libc.so.6

mimedefang only needs these libraries:
   NEEDED               libmilter.so.1.0
   NEEDED               libpthread.so.0
   NEEDED               libnsl.so.1
   NEEDED               libc.so.6

Running strings on all of the above mentioned libraries reveals that 
libmilter.so is the only library with the error string:
  # strings /lib64/libmilter.so.1.0 | grep connect'.*'unknown
%s: connect[%ld]: unknown family %d

On my Fedora 25 milter-greylist is dynamically linked:
/usr/sbin/milter-greylist: ELF 64-bit LSB shared object, x86-64, version 
1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, 
for GNU/Linux 2.6.32, 
BuildID[sha1]=04cf4466583553af0ba55ffc3b910e813ae357b8, stripped

/john