<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><meta content="text/html;charset=UTF-8" http-equiv="Content-Type"></head><body ><div style="font-family: Verdana, Arial, Helvetica, sans-serif; font-size: 10pt;"><div>Hi all - just want to report a problem I solved recently but wanted to get some insights on what was causing the problem.<br></div><div><br></div><div>About me - learnt some unix at university (20 years ago) but nothing too serious. Recently (1 month ago) acquired own domain name and now poking around the cloud computing / VPS thing.<br></div><div><br></div><div>Project - hand-rolling my own VPN setup on a Ubuntu 18.04 VPS. OpenVPN is easy since it is a git-clone thing and then just follow the openvpn-install script. I wanted to add on the Stunnel wrapper because intended to use the VPN in China and apparently their firewall does deep packet inspection and can recognize (and block) openvpn traffic.<br></div><div><br></div><div>Problem - when I set up my stunnel using 127.0.0.1 as the connect destination; it doesn't seem to work (I can see from openvpn window that things seem to pipe through stunnel but then immediately the connection is terminated). If I replace the 127.0.0.1 with IP of the box I am using (say for example 1.2.3.4); everything works! The FQDN is ok as well; as long as I don't use 127.0.0.1<br></div><div><br></div><div>Specifically the stunnel.conf:<br></div><div><br></div><div>[OpenVPN]<br></div><div>Accept = 443 # clients connect through 443 to further avoid potential blocking<br></div><div>Connect = 127.0.0.1:1194 #<- this line won't work; but if I replace with 1.2.3.4:1194 then it will work!<br></div><div><br></div><div>Question - My problem is fixed but I am curious if there is any insights on why this is happening given that 1.2.3.4 and 127.0.0.1 are the same machine?<br></div><div><br></div><div><br></div></div><br></body></html>