# Bro: detectiong OS probes **URL:** \ **Category:** Zeek\ **Created:** [July 18, 2001, 7:25am UTC](https://community.zeek.org/t/bro-detectiong-os-probes/172 "2001-07-18T07:25:17Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![Vern](https://yyz1.discourse-cdn.com/flex011/user_avatar/community.zeek.org/vern/32/630_2.png) [@Vern](https://community.zeek.org/u/Vern)\ **Post date:** [July 18, 2001, 7:25am UTC](https://community.zeek.org/t/bro-detectiong-os-probes/172/1 "2001-07-18T07:25:17Z")
> Lot of OS probes works by sending a combination of flags like > > SFU12, SF12 etc and seeing how the OS behaves. I was wondering how to detect > these kind of probes using bro . > > I know it can be done easily in the TCPConnection::NextPacket() > where you have the syn,fin,rst and other flags in separate variables. > Probably i could look for those pattern call the Weird(). > > But is that the way to go about it ? Or should the detection be done > at the bro-script level. The right way to do it is either via Weird(), or (better) by introducing a new event handler, something like:   event strange\_TCP\_flag\_combo(c: connection, SYN: bool, FIN: bool, RST: bool, ACK: bool, PSH: bool, URG: count) Your policy script could then decide how to react to specific combinations.     Vern ---
**Author:** ![Trinh\_Anh\_Tuan](https://avatars.discourse-cdn.com/v4/letter/t/df788c/32.png) [@Trinh\_Anh\_Tuan](https://community.zeek.org/u/Trinh_Anh_Tuan)\ **Post date:** [November 6, 2001, 9:35am UTC](https://community.zeek.org/t/bro-detectiong-os-probes/172/2 "2001-11-06T09:35:54Z")
Hello, I would like to have reports cyclically of my network usage beside the intrusion detection, so I have a short script like the attached file. Unfortunatelly, bro seems do nothing with reporting. It isn't documented, so can you draw me a way of doing that? Cordially, [ShowFilter.bro](https://community.zeek.org/uploads/short-url/mpQRDY0vWEoTHCLZXw0nxP9NGF2.bro) (686 Bytes) ---
**Author:** ![system](https://canada1.discourse-cdn.com/flex011/uploads/zeek/original/1X/f09d732bc2cc7c7cc7e35db67cf4e1d5233ce7a7.png) [@system](https://community.zeek.org/u/system)\ **Post date:** [May 6, 2022, 3:36pm UTC](https://community.zeek.org/t/bro-detectiong-os-probes/172/3 "2022-05-06T15:36:21Z")