In Linux, simulate slow traffic incoming traffic to port e.g. 54000

Question

is there a way in Linux to simulate slow traffic inbound to my server at a specific port? I looked at NETEM but it only seems to WAN wide.

Answer 1

An example of limiting all traffic matching tcp (protocol 6) destination port of 54000 at 256Kbits inbound to eth0, using tc...

As root...

tc qdisc add dev eth0 handle ffff: ingress
tc filter add dev eth0 parent ffff: protocol ip prio 50 u32 \
    match ip  protocol 6 0xff \
    match ip dport 54000 0xffff police rate 256kbit burst 10k drop \
    flowid :1

You can monitor it like this... notice the dropped number for ffff, below

[mpenning@Bucksnort ~]$ sudo tc -s qdisc show
qdisc pfifo_fast 0: dev eth0 root refcnt 2 bands 3 priomap  1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1
 Sent 17796311917 bytes 5850423 pkt (dropped 0, overlimits 0 requeues 0)
 rate 0bit 0pps backlog 0b 0p requeues 0
qdisc ingress ffff: dev eth0 parent ffff:fff1 ----------------
 Sent 140590 bytes 1613 pkt (dropped 214, overlimits 0 requeues 0)
 rate 0bit 0pps backlog 0b 0p requeues 0
qdisc pfifo_fast 0: dev eth1 root refcnt 2 bands 3 priomap  1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1
 Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
 rate 0bit 0pps backlog 0b 0p requeues 0
[mpenning@Bucksnort ~]$

To delete all ingress traffic filters:

tc qdisc del dev eth0 ingress