It may be relevant that I have two versions of openssl installed -- I 
installed 0.9.7e-3 on top of 0.9.7a-46, because there are some things 
that depend on the old libraries.  Perhaps this is the problem.

The problem here, it turns, out is that the getnameinfo function 
provided in libbind in bind-9.3.1rc1-3 doesn't obey the 
NI_NUMERICSERV flag.  It's returning a port name instead of a port 
number to sendmail, and sendmail feeds this into SASL, which 
complains about it because it's expecting a port number.  Bind-9.3.0-
2 doesn't have this problem, presumably because it doesn't provide 
getnameinfo -- it relies on libc to provide it, and the version in 
libc obeys NI_NUMERICSERV.

This problem occurs because the wrong include path has been used
to compile libbind using code. 
/usr/include/netdb.h defines:
    # define NI_NUMERICSERV 2
while 
/usr/include/bind/netdb.h defines:
    #define NI_NUMERICSERV  0x00000008

To use libbind, you must either specify 
   -I/usr/include/bind
in your compile command, or change your #include directives for
libbind headers (eg. netdb.h) to:
    #include <bind/netdb.h>

sendmail must be recompiled with these include path changes in
order to continue using libbind. 

This bug is now fixed with sendmail-8.13.3-1.2, to be released in 
FC4/Rawhide shortly.

Unfortunately, this change causes sendmail 8.13.3-1.2 to crash on start-up for
me on x86_64, running something as simple as:

sendmail oliva@lsd.ic.unicamp.br

It works fine on an i686 box.  Reverting to 8.13.3-1.1 restores a functional
sendmail.

Fixed in RPM sendmail-8.13.3-2. This version is using libresolv from glibc again
instead of the libbind. 
Support for libbind was dropped, but option NAMED_BIND is still active for
DNSMAPs using libresolv.

Please test this new version.