What is TlsException("(54, 'ECONNRESET')",)?


When loading a web page on a mobile device using chrome and monitoring the traffic with mitmdump, I see that there are quite a few “Cannot establish TLS with client (sni: HOST): TlsException(”(54, ‘ECONNRESET’)",)" being thrown.

After attaching google’s remote debugging to the mobile device, I see that there are errors in the console about bad http requests with error net::ERR_NAME_NOT_RESOLVED. Also, I checked for pinning via chrome://net-internals/#hsts, and the vast majority of the hosts for which the exception is thrown do not implement pinning.

Does the TlsException 54 correspond to the bad http requests? Or does it mean something completely different?

Thanks! :slight_smile:

Mitmproxy version: 2.0.2 (release version)
Python version: 3.6.1
Platform: Darwin-16.6.0-x86_64-i386-64bit
SSL version: OpenSSL 1.1.0f 25 May 2017
Mac version: 10.12.5 (’’, ‘’, ‘’) x86_64

ECONNRESET is short for “Error Connection Reset” - the other end has closed/reset the TCP connection. Why that is happening is up to your interpretation. :slight_smile: