NSPR_LOG_MODULES=timestamp,nsHttp:3,sync NSPR_LOG_FILE=/tmp/ff.log /path/to/firefox/firefox

2017-01-07 19:18:49.799922 UTC - -1371059392[b726e9c0]: Http2Session::ALPNCallback version=303
2017-01-07 19:18:49.981528 UTC - -1220458752[b726e0c0]: http request [
2017-01-07 19:18:49.981551 UTC - -1220458752[b726e0c0]:   POST / HTTP/1.1
2017-01-07 19:18:49.981560 UTC - -1220458752[b726e0c0]:   Host: ocsp.int-x3.letsencrypt.org
2017-01-07 19:18:49.981567 UTC - -1220458752[b726e0c0]:   User-Agent: Mozilla/5.0 (X11; Linux i686; rv:4
3.0) Gecko/20100101 Firefox/43.0
2017-01-07 19:18:49.981574 UTC - -1220458752[b726e0c0]:   Accept: text/html,application/xhtml+xml,applic
ation/xml;q=0.9,*/*;q=0.8
2017-01-07 19:18:49.981580 UTC - -1220458752[b726e0c0]:   Accept-Language: en-US,en;q=0.5
2017-01-07 19:18:49.981589 UTC - -1220458752[b726e0c0]:   Accept-Encoding: gzip, deflate
2017-01-07 19:18:49.981595 UTC - -1220458752[b726e0c0]:   DNT: 1
2017-01-07 19:18:49.981604 UTC - -1220458752[b726e0c0]:   Content-Length: 85
2017-01-07 19:18:49.981611 UTC - -1220458752[b726e0c0]:   Content-Type: application/ocsp-request
2017-01-07 19:18:49.981617 UTC - -1220458752[b726e0c0]:   Connection: keep-alive
2017-01-07 19:18:49.981639 UTC - -1220458752[b726e0c0]: ]
2017-01-07 19:18:50.071135 UTC - -1371059392[b726e9c0]: http response [
2017-01-07 19:18:50.071174 UTC - -1371059392[b726e9c0]:   HTTP/1.1 200 OK
2017-01-07 19:18:50.071195 UTC - -1371059392[b726e9c0]:   Server: nginx
2017-01-07 19:18:50.071203 UTC - -1371059392[b726e9c0]:   Content-Type: application/ocsp-response
2017-01-07 19:18:50.071210 UTC - -1371059392[b726e9c0]:   Content-Length: 527
2017-01-07 19:18:50.071218 UTC - -1371059392[b726e9c0]:   Etag: "3FFFC13100849446EA3D8FA68B0077AF4792776825416386C5CF76104592E0CE"
2017-01-07 19:18:50.071225 UTC - -1371059392[b726e9c0]:   Last-Modified: Wed, 04 Jan 2017 00:00:00 UTC
2017-01-07 19:18:50.071233 UTC - -1371059392[b726e9c0]:   Cache-Control: public, no-transform, must-revalidate, max-age=24762
2017-01-07 19:18:50.071240 UTC - -1371059392[b726e9c0]:   Expires: Sun, 08 Jan 2017 02:11:32 GMT
2017-01-07 19:18:50.071247 UTC - -1371059392[b726e9c0]:   Date: Sat, 07 Jan 2017 19:18:50 GMT
2017-01-07 19:18:50.071254 UTC - -1371059392[b726e9c0]:   Connection: keep-alive
2017-01-07 19:18:50.071259 UTC - -1371059392[b726e9c0]: ]