Hi. I'm not sure where to start troubleshooting the problem and am hoping someone can give some suggestions. It appears that when sending mail to some places using my FC3 box that mail gets lost. I do not receive any bounced message nor does the mail get received. For my MUA I use mutt with fetchmail grabbing mail from my hosting service. I was using exim as my mta with smarthost setup for outgoing mail which authenticated to my hosting service. I tried sending a message to a mailing list on smartgroups and did not see it posted. I was receiving mail just fine from the list and did confirm I was subscribed under the correct email address. I then went to my Windows box using Outlook Express and sent a message to the smartgroups list and it went through. The Outlook outgoing mail is set up to use my hosting service as it's smtp authenticator as well. Basically the difference is that it did not go through my Linux MTA. I thought for some reason the problem may have been exim so I switched it to using postfix. Configured it to authenticate outgoing mail to my hosting service and still get the same results. So far I've mainly noticed this with the smartgroups.com domain but a few others have told me they have not received mail from me when I know I sent out messages. The logs of exim or postfix show the message went out successfully. Either that or I am not sure of what to look for exactly. Any ideas?