푸뽀 2023-11

질문글 보고 저도 테스트로 드롭이나 딜레이 할 수 있으면 좋겠다고 생각해서 검색해보니,
tc 명령에서 netem(네트워크 에뮬레이트) 으로 드롭이나 딜레이 할 수 있다고 합니다.

https://www.pico.net/kb/how-can-i-simulate-delayed-and-dropped-packets-in-linux/

    Add 10ms of delay to every packet transmitted on eth0:
    $ tc qdisc add dev eth0 root netem delay 10ms

    Add 10ms of delay and 20ms of jitter to every packet bridged by br0:
    $ tc qdisc add dev br0 root netem delay 10ms 20ms

    Randomly drop approximately one percent of packets transmitted on eth1:
    $ tc qdisc add dev eth1 root netem loss 1%

전설속의미… 2023-11

iptables로 drop의 경우는, 확률을 지정해서 되긴 하더라구요

====

## DROP packet with ratio
❯ uname -mrs
Linux 5.10.199-190.747.amzn2.x86_64 x86_64

❯ sudo iptables -A INPUT -p icmp --icmp-type echo-request -m statistic --mode random --probability 0.50 -j DROP

❯ sudo iptables -L --line-numbers
Chain INPUT (policy ACCEPT)
num  target    prot opt source              destination
1    DROP      icmp --  anywhere            anywhere            icmp echo-request statistic mode random probability 0.500000
00000 # <================== !!!

Chain FORWARD (policy DROP)
....

❯ ping -c 10 43.200.105.82
0 ▁ 10 ▂ 20 ▃ 30 ▄ 40 ▅ 50 ▆ 60 ▇ 70 █ 80 ▁ 90 ▂ 100 ▃ 110 ▄ 120 ▅ 130 ▆ 140 ▇ 150 █ 160 ▁ 170 ▂ 180 ▃ 190 ▄ 200 ▅ 210 ▆ 220 ▇
230 █ ∞
PING 43.200.105.82 (43.200.105.82): 56 data bytes
▁▁!▁!▁▁!!
 4/  9 (44%) lost;    3/  4/  5ms; last:    5ms
 4/  9 (44%) lost;    3/  4/  5/  1ms (last 5)
--- 43.200.105.82 ping statistics ---
10 packets transmitted, 5 packets received, 50.0% packet loss # <============ !!!
round-trip min/avg/max/stddev = 3.628/4.190/5.252/0.619 ms