unmatched_HTTP_reply in weird.log


Recently my Bro cluster started producing a lot of unmatched_HTTP_reply messages in weird.log and seemed to also stop logging outbound GET requests in http.log. I did some testing by following both Bro logs as I browsed to various websites and it looks like every time I visit a new site, the initial GET request doesn't get logged and a weird is generated. As such I'm wondering if this may be an indication that Bro is only seeing half the conversation? I can trace the change in logging behavior to a specific day, but I can't find any indication that there were any changes locally that would have stopped Bro from seeing any particular traffic. Anyone thoughts? Am I interpreting the logs correctly?


Most likely this is a problem upstream from Bro.

To rule out bro as a problem here do something like

    tcpdump -nn -i eth1 host your.ip.address and port 80

if you only see one side of the conversion in tcpdump as well that will
rule bro out as the problem.