I Use Wireshark to monitor the network traffic while Outlook Express tries to send a mail.OE (or the kernel, if you like) emits TCP "SYN" datagrams to establish a connection to the server. The IP address is correct, see below.There are three such SYN packets before OE gives up,Then I run "telnet smtp.online.no 25" in a command window. This produces a fourth SYN packet and immediately (just a few milliseconds) a response "SYN-ACK" packet. In the telnet window the server's greeting appears. I type QUIT and the connection finishes normally.Then I click the "Send and Receive" button in OE again, and this time OE gets the connection and sends the mail and all is as it should. But this pattern has repeated some 6-7 times in the course of the last few days. Yesterday I got the error box in OE, went upstairs to my Linux box and issued the telnet command and got the greeting banner message right away. Back downstairs I clicked Send and Receive again, but again it failed. I went back up and tried telnet again, and the response was immediate. Back at the XP and OE I clicked Send and Receive for the third time, and it failed. Then I figured out how to run telnet on the XP (I tried in a cygwin window, but that did not work), and as soon as I had had a telnet session (on the smtp port) with the server, then OE did work flawlessly.The two computers are on a home network with a single shared external IP address, so the server outside should not see any difference. Yet it seems like the server refuses to answer only if OE is the originator of the connection, and only if I have not had any recent telnet connection from the same computer.Any ideas what could cause this?1 person needs an answerI do too