I have seen this problem posted on LinuxQuestions in reference to an earlier Sendmail build but the solution is not available due to an insecure link. I believe the solution is in the configuration of site.config.m4 but I am stumped.

Below is the error I get attempting to build Sendmail-8.18.1:

/bin/ld: domain.o: in function `getmxrr':
domain.c.text+0x156): undefined reference to `__res_search'
/bin/ld: domain.c.text+0x240): undefined reference to `__dn_skipname'
/bin/ld: domain.c.text+0x378): undefined reference to `__res_query'
/bin/ld: domain.c.text+0x536): undefined reference to `__dn_expand'
/bin/ld: domain.c.text+0x59f): undefined reference to `__dn_expand'
/bin/ld: domain.o: in function `dns_getcanonname':
domain.c.text+0x113e): undefined reference to `__res_querydomain'
/bin/ld: domain.c.text+0x1327): undefined reference to `__dn_skipname'
/bin/ld: domain.c.text+0x1437): undefined reference to `__dn_expand'
/bin/ld: domain.c.text+0x155a): undefined reference to `__dn_expand'
/bin/ld: sm_resolve.o: in function `dns_lookup_int':
sm_resolve.c.text+0x246): undefined reference to `__res_search'
/bin/ld: sm_resolve.c.text+0x433): undefined reference to `__res_search'
/bin/ld: sm_resolve.c.text+0x54a): undefined reference to `__dn_expand'
/bin/ld: sm_resolve.c.text+0x5f7): undefined reference to `__dn_expand'
/bin/ld: sm_resolve.c.text+0x829): undefined reference to `__dn_expand'
/bin/ld: sm_resolve.c.text+0x8a8): undefined reference to `__dn_expand'
/bin/ld: sm_resolve.c.text+0x998): undefined reference to `__dn_expand'

My site.conf.m4:

dnl # SASL2 (smtp authentication)
APPENDDEF(`confENVDEF', `-DGSASL -DHASFLOCK')
APPENDDEF(`conf_sendmail_LIBS', `-lgsasl -lresolv')
dnl #
dnl # STARTTLS (smtp + tls/ssl)
APPENDDEF(`conf_sendmail_ENVDEF', `-DSTARTTLS')
APPENDDEF(`conf_ENVDEF', `-D_FFR_SMTP_SSL')
APPENDDEF(`conf_sendmail_LIBS', `-lssl -lcrypto -L/usr/lib64')
APPENDDEF(`confLIBDIRS', `-L/usr/lib64')
APPENDDEF(`confINCDIRS', `-I -L/usr/include')

I haven't built since 8.17.2. I get:
I get the same with 8.17.2 - which I have successfully built. Don't know.

Hi,

FYI, using your site.conf.m4, replacing just gsasl with sasl2 as I use cyrus-sasl, sendmail-8.18.1 was compiled successfully on Slackware64-current:

Thank you for responding. I went over to Cyrus SASL but still get the same error. I see others have encountered this problem, too. Perhaps it has to do with Build not finding libresolv?

The sasl package is irrelevant in your case...
The problem is with resolv.h that cannot be found by the compiler.

You didn't mention your distro, but for Slackware libresolv and the header resolv.h are provided by glibc
On a different distro you need to install the glibc development package.

I use Fedora. Slackware was the first Linux distro I used eons ago. You may be right but both the header and the library of libresolv is installed and loaded in the LDCache. Also, it is in /usr/include so Sendmail Build should be able to find it the path is stated in site.conf.m4

The fix was to add -lresolv to the LIBS variable in the makefile in the object/sendmail directory - then Build completes. (Important to use only ./Build when doing this and not, of course ./Build -c .) The mystifying thing is that resolv.h is in the /usr/include directory which is referenced by confINCDIRS in my site.conf.m4 file. So it is odd that the Build program was not able to locate it.

1 members found this post helpful.

In the end I did not have to use -lresolv either in the makefile or in site.config.m4. It may have been changing DSASL2 to DSASL=2 or using -DHASFLOCK=1 instead of DHASFLOCK (though the latter should not have made a difference) - or adding -ldb to conf_sendmail_LIBS. But this is what worked in the end with Berkley db correctly accessing flock:

dnl # SASL2 (smtp authentication)
APPENDDEF(`confENVDEF', `-DSASL=2 -DHASFLOCK=1')
APPENDDEF(`conf_sendmail_LIBS', `-lsasl2')
dnl # STARTTLS (smtp + tls/ssl)
APPENDDEF(`conf_sendmail_ENVDEF', `-DSTARTTLS')
APPENDDEF(`conf_ENVDEF', `-D_FFR_SMTP_SSL')
APPENDDEF(`conf_sendmail_LIBS', `-lssl -lcrypto -ldb -L/usr/lib64')
APPENDDEF(`confLIBDIRS', `-L/usr/lib64')
APPENDDEF(`confINCDIRS', `-I/usr/include')