It seems the delay in submitting message is due to reverse lookup of my intranet ip address which is not resolvable. I was able to eliminate the delay by setting TCPDOPTS to -nodnslookup and -noidentlookup in esmtpd. However, I don't want to disable it globally and would prefer to set these options just for my local subnet and specific ip addresses. It is not clear from the documentation whether I can do this selectively in the smtpaccess file. If so, would the syntax be:

my.sub.net<tab>-nodnslookup -noidentlookup

and makesmtpaccess??