4.10 My clients sometimes get 30 to 40 second delays when they try and send mail through our mailhost, but it works fine other than this delay. We've checked everything and there just doesn't seem to be anything obviously wrong with our configuration. What else should we check?

One place this problem arises from is when the ident daemon is being used to track the source of incoming connections. Try adding this to your macro config file on your mail host: define(`confTO_IDENT',`0s')dnl (note that this turns off ident).