Inject latency and loss

Simulate WAN latency/packet loss for testing; remove with tc qdisc del

tc qdisc add dev <name> root netem delay 100ms loss 1% && tc -s qdisc show dev <name>
tool
iproute212 commands
tags
iproute2networkperformancetroubleshooting

More iproute2 commands

  • Remove netem qdisc
    tc qdisc del dev <name> root

    Drop the root qdisc to restore normal traffic after netem testing

  • Watch route/link events
    ip monitor all

    Live stream of route/link/addr/neigh changes; great for flapping debug

  • Bridge FDB and ports
    bridge fdb show br <name>; bridge link show

    Inspect L2 forwarding DB (MAC->port) and bridge port states

  • Per-socket TCP internals
    ss -tip state established '( dport = :443 )'

    Show rtt/cwnd/retrans per socket for 443; pinpoint slow/lossy peers

  • Kill sockets by filter
    ss -K dst <ip> dport = :8080

    Forcibly close matching sockets (kernel>=4.9); needs CONFIG_INET_DIAG_DESTROY

all 12 iproute2 commands