Hi, I hoped that this bug was fixed in Panther, but it isn't:
This happens Only in Mail.app when I am on a specif network - (Specifically FreeServe AnyTime via ISDN in the UK - with NAT and DHCP).
My brother uses Entourage and has no such problem. When I use Mail on other networks - I have no problems either - Also the .mac SMTP server always works - even when the others don't.
I have submitted a bug report to Radar - but have little hope it not being marked "Cannot reproduce"
Does anyone else suffer from this problem? If we can narrow down what causes it - there is a better chance of Apple Fixing it.