We have a hard time debugging 400 errors on our website. We have a lot of errors like this:
10.0.0.1 - - [08/Oct/2018:14:28:07 +0200] "GET /les-news/palmares/detail/article/la-lettre-de-motivation-ideale-pour-une-demande-de-stage-5224/ HTTP/1.1" 400 131844 "https://www.google.com/" "Mozilla/5.0 (Linux; Android 7.0; TECNO K7 Build/NRD90M) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.91 Mobile Safari/537.36"
A user reported the problem by email and it was fixed by resetting it's cookies in his browser for other resetting cookies was not enough (but we can't be sure it was correctly done).
The platform is quite complicated and handled by a F5 load balancer, depending on the path the request to forwarded to different servers.
What I'd like at first is being able to reproduce the error because when accessing the URL we don't have any and everything works fine.
We noticed that most of error comes from Android/Chrome: about 85% of all 400 errors.
Here is a full log:
timestamp October 8th 2018, 16:26:52.000 version 1 _id BmQSVGYB5vF-Dw_g1gVi _index f5_access-2018.10.08 _score - t _type doc t agent Mozilla/5.0 (Linux; Android 8.1.0; MI 8 Build/OPM1.171019.026) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.91 Mobile Safari/537.36 client_ip 10.0.0.1 client_port 41,068 facility local2 host mydomain.fr httpversion 1 id 2,503,307,391 length 0 logsource mydomain.network.local message virtual=/Common/mydomain.fr_HTTP client_ip=10.0.0.1 client_port=41068 lb_server=10.153.161.12:80 host=mydomain.fr request_port=80 username= request="GET / HTTP/1.1" server_status=400 content_length=0 resp_time=23 user_agent="Mozilla/5.0 (Linux; Android 8.1.0; MI 8 Build/OPM1.171019.026) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.91 Mobile Safari/537.36" referer=http://mydomain.fr/article/100-millions-d-euros-sciences-po-lance-la-plus-grande-levee-de-fonds-de-son-histoire_095255b4-caef-11e8-896c-7d05c73a49da/ ID=2503307391 timestamp=2018-10-08T16:26:52+0200 pool=/Common/POOL_ETUDIANT_v2_nocache pool POOL_MYDOMAIN_v2_nocache program f5_access referer http://mydomain.fr/article/100-millions-d-euros-sciences-po-lance-la-plus-grande-levee-de-fonds-de-son-histoire_095255b4-caef-11e8-896c-7d05c73a49da/ request / request_port 80 server_ip 10.0.0.1 server_port 80 severity Informational status 400 stdstatus 4xx stdvirtual mydomain_fr_HTTP tags f5_access time 23 timestamp October 8th 2018, 16:26:52.000 type f5_access verb GET virtual mydomain.fr_HTTP