Stuck trying to config sendmail for virtual domains

[Michael <openbsd@magicpubs.com>]

I've been trying (for days now) to configure sendmail to support multiple 
domain names as per the "Virtual Hosting with Sendmail" page at:

  <http://sendmail.org/virtual-hosting.html>

I think i have BIND configured correctly, complete with an MX record for 
my domain, and everything appears to resolve correctly using nslookup, 
dnsquery and ping.

I suspect my problem might be that sendmail isn't listening correctly for 
(or accepting?) the virtual domain, but i could be wrong.  When i try 
sending mail to this virtual domain, nothing happens immediately, but 
eventually i get a "Warning: could not send message for past 4 hours" 
eMail, which contains this line:  "Deferred: Connection refused by 
mail.yourdomain.com"

Does "refused" mean sendmail is configured for and listening on behalf of 
"yourdomain.com", but is rejecting (or ignoring) everything for it?  Is 
this a relaying issue of some kind?  Any insight would be greatly 
appreciated.  Here are the specifics of what i've tried...

To create a "master.mc" file i cloned 
/usr/share/sendmail/cf/openbsd-proto.mc and immediately after the 
"OSTYPE(openbsd)" line inserted:

  DOMAIN(yourdomain.com)dnl
  FEATURE(`virtusertable', `hash /etc/mail/virtusertable')dnl

The "yourdomain.com.m4" file contains:

  VERSIONID(`@(#)yourdomain.com.m4   1.0 (yourdomain.com) 1-Feb-2003')
  define(`confMAX_HEADERS_LENGTH', `32768')dnl
  FEATURE(`use_cw_file')dnl

When i do a "cat sendmail.cf | grep yourdomain.com" i get:
      
  #####  @(#)yourdomain.com.m4   1.0 (yourdomain.com) 1-Feb-2003  #####

Which leads me to believe the "yourdomain.com.m4" file is compiling when 
i build the sendmail.cf file (as that comment is directly from the 
yourdomain.com.m4 file), but it leaves me wondering if i shouldn't be 
seeing more references to "yourdomain.com" in my sendmail.cf file?  Now 
as i understand it, the "use_cw_file" directive causes sendmail to read 
the "/etc/mail/local-host-names" to determine which domains to listen 
for.  My local-host-names contains "yourdomain.com",  
"mail.yourdomain.com" and "porthos.yourdomain.com".

I do not have a "/etc/mail/generics-domains" file as i am not concerned 
about reverse-mapping the domain and believe it to be optional.

The MX record (from a dnsquery) looks like this:

  yourdomain.com. 7200    IN      MX      10 mail.yourdomain.com.

When i do a "echo '$=w' | sudo sendmail -bt" i get:

  ADDRESS TEST MODE (ruleset 3 NOT automatically invoked)
  Enter <ruleset> <address>
  > [IPv6:::1]
  [192.168.1.xxx]
  [IPv6:xxxx::1]
  porthos
  localhost
  [localhost.mydom.com]
  localhost.mydom.com
  [127.0.0.1]
  mail.yourdomain.com
  porthos.yourdomain.com
  [IPv6:xxxx::xxx:xxxx:xxxx:xxxx]
  porthos.mydom.com
  > 

[Note:  "porthos" is the name of the machine and its domain is set to 
"mydom.com".  I've masked out some numbers with x's for security reasons 
and because i don't think they are pertinent to this discussion.] 

To compile my sendmail.cf file, i'm issuing this command from my home 
directory (not root):

  m4 /usr/share/sendmail/m4/cf.m4 master.mc > sendmail.cf

This seems to work (originally, i was able to reproduce the stock OpenBSD 
sendmail.cf, with a different build date, of course.)  Once built, i then 
move the newly built sendmail.cf into place with:

  sudo mv sendmail.cf /etc/mail/sendmail.cf

and issue a:

  sudo kill -HUP `sudo head -1 /var/run/sendmail.pid`

To create the virtusertable.db i did:

  cd /etc/mail
  sudo makemap hash virtusertable < virtusertable

And it does contain a catchall entry:

  @yourdomain.com  mylocalid

where "mylocalid" is my local login ID.

I do have a "relay-domains" file, but am not sure i've told sendmail to 
pay any attention to it (haven't changed the default config in respect to 
relaying; don't want to open up the box to spammers inadvertently):

  .mydom.com
  192.168.1
  localhost

I'm now totally convinced that sendmail configuration is a black art.  
Should i be sacrificing a goat at the altar or something?  Any help, 
insights, pointers, magic spells, incantations, etc. would all be most 
appreciated.  TIA.