After a lot of fruitless tinkering at the Linux end I came up with a pair of RDP files, one working and the other not. (After translation from UTF-8) the difference is:
$ diff -u9999 broken.txt working.txt --- broken.txt 2017-09-16 16:47:55.076161839 +0100 +++ working.txt 2017-09-16 16:47:58.500101132 +0100 @@ -1,48 +1,48 @@ screen mode id:i:2 use multimon:i:0 desktopwidth:i:1920 desktopheight:i:1200 session bpp:i:32 winposstr:s:0,1,334,51,1705,1038 compression:i:1 keyboardhook:i:2 audiocapturemode:i:0 videoplaybackmode:i:1 -connection type:i:6 +connection type:i:5 networkautodetect:i:0 bandwidthautodetect:i:1 displayconnectionbar:i:1 enableworkspacereconnect:i:0 disable wallpaper:i:0 allow font smoothing:i:1 allow desktop composition:i:1 disable full window drag:i:0 disable menu anims:i:0 disable themes:i:0 disable cursor setting:i:0 bitmapcachepersistenable:i:1 full address:s:wampoon.anjou.terraraq.org.uk audiomode:i:0 redirectprinters:i:1 redirectcomports:i:0 redirectsmartcards:i:1 redirectclipboard:i:1 redirectposdevices:i:0 autoreconnection enabled:i:1 authentication level:i:2 prompt for credentials:i:0 negotiate security layer:i:1 remoteapplicationmode:i:0 alternate shell:s: shell working directory:s: gatewayhostname:s: gatewayusagemethod:i:4 gatewaycredentialssource:i:4 gatewayprofileusagemethod:i:0 promptcredentialonce:i:0 use redirection server name:i:0 rdgiskdcproxy:i:0 kdcproxyname:s: gatewaybrokeringtype:i:0 drivestoredirect:s: username:s:richard https://technet.microsoft.com/en-us/library/gg607280(v=ws.10).aspx describes the connection types. 5 is 'WAN (10 Mbps or higher with high latency)' and 6 is 'LAN (10 Mbps or higher)'. (My actually connectivity is entirely local: I am connecting from Windows 10 to a Hyper-V VM running Debian, all on the same physical hardware.) Whether this is the same problem anyone else has, I don't know! ttfn/rjk
