Gisle: thank you for your response.
Let's focus on the different behaviour with IPv4: Using libcurl in an application, without firewall operating, attempting to connect to bbc.co.uk, I obtain a hang with * Trying 151.101.64.81:80... the only output written. Using curl.exe I obtain >curl -v -4 bbc.co.uk * Trying 151.101.64.81:80... * Connected to bbc.co.uk (151.101.64.81) port 80 (#0) > GET / HTTP/1.1 > Host: bbc.co.uk > User-Agent: curl/7.71.0-DEV I only have one dll in the system, which I have verified both applications are loading. How could I investigate the reason for the difference in behaviour? It can't fundamentally be ISP related, since curl.exe gets through. With thanks again for any ideas! -- MS ------------------------------------------------------------------- Unsubscribe: https://cool.haxx.se/list/listinfo/curl-library Etiquette: https://curl.haxx.se/mail/etiquette.html
