Having issues with external emails. Currently have user that logs on and has mailbox under 'jsmith@domain.com'. Internal email works ok.

Exchange gets email from POP and external email is 'John.Smith@domain.com'. Email is forwarded to 'jsmith@domain.com' just fine.

However, issue is if email sent from internal to external, then when external user replies, it tries to send to 'jsmith@domain.com'. External email shows "From:" as 'jsmith@domain.com'.

Any ideas on how to fix this?

You would have to have every external email user configure their email reply to 'John.Smith@domain.com' or have the email servers adminstrator globally set the same, if possible.

I am surprised you don't have more forwarding/lost email/bounced email issues with this setup.

Why aren't you just using one or the other email server for everything?

Luckily there are only two of these email addresses like this.

Unfortunately, it's a political game with the person responsible for administering the POP accounts and I personally wouldn't have done it that way! :)

I can sure understand that.

Just have the users/admins change the reply to address in the users outlook settings on those accounts.

Seems easiest. Best of luck!

Do your self a favor and get rid of the POP collector. Theres no point in having exchange if your going to have your email delivered to it via POP.It was designed as an MTA with SMTP not POP. Less administrative overhead and complication and more control when you use SMTP.