I have a number of Ubuntu Server 16.04 LTS instances running as virtual machines on Microsoft Azure. Since a week, we are having problems uploading bigger files via both SFTP and HTTPS to these servers.
The strange thing is that nothing changed on the servers and the problems only happen on specified networks.
The symptoms are:
- HTTPS upload:
net::ERR_SSL_BAD_RECORD_MAC_ALERT
is shown in the error console - SFTP upload: abort after a few megabtyes. On the server, the logfile /var/log/auth.log shows the following error:
fatal: ssh_dispatch_run_fatal: Connection from 81.83.5.23 port 63154: message authentication code incorrect
What is really weird is that this only happens on certain networks from specific internet providers in Belgium. Other providers don't have this problem, so I'm suspecting the internet provider is the cause of this problem.
Any ideas how this can be troubleshooted or fixed?