Linux
kernel
iperf
dropwatch
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環境

CentOS Linux release 7.2.1511

dropwatchとは

カーネルによって落とされたパケットをモニタリングできるインタラクティブなツール

Install

# yum install dropwatch

Usage

# dropwatch
Initalizing null lookup method
dropwatch> start
Enabling monitoring...
Kernel monitoring activated.
Issue Ctrl-C to stop monitoring

1 drops at location 0xffffffff8151a358

^CGot a stop message
dropwatch> exit
Shutting down ...
#

Example

以下の構成でServer1→Server3に対してipefを使ってトラフィックを流し、Server2でdropwatchを実行する。

-------------------------------
Server1 -- Server2 -- Server3
-------------------------------

実行コマンド(Server1)

# iperf -c [Server3] -t 10 -i 1 -M 100

出力結果


dropwatch> start
Enabling monitoring...
Kernel monitoring activated.
Issue Ctrl-C to stop monitoring
6 drops at location 0xffffffff8151a1fb
3 drops at location 0xffffffff8151a1fb
9 drops at location 0xffffffff8151a1fb
30313 drops at location 0xffffffff8151a1fb
826 drops at location 0xffffffff8151a1fb
34127 drops at location 0xffffffff8151a1fb
2076 drops at location 0xffffffff8151a1fb
34339 drops at location 0xffffffff8151a1fb

結構でますね。。。

参考文献

man dropwatch
http://research.sakura.ad.jp/2013/12/16/dropwatch/