I am trying to 'man in the middle' a device on my wifi network. I have configured it to use my Linux machine (also in the wifi network) as a default gateway.

On the Linux (attack) host, I switched on IPv4 forwarding using

# sysctl -w net.ipv4.ip_forward=1

Then I start looking at the traffic from the victim device using wireshark. I then saw that the attack machine sends ICMP redirect packets to the victim device, pointing it to the actual default gateway in the network. That is, obviously, not what I want it to do.

Then I tried disabling ICMP redirects using

# sysctl -w net.ipv4.conf.all.send_redirects=0

That seemed to work, but after a while the redirect packets started to appear again...

Any clues to what I can do to fix?

1 Answer 1


In my experience this

sysctl -w net.ipv4.conf.all.send_redirects=0

will not work properly on some systems what works for me is

echo 0 | tee /proc/sys/net/ipv4/conf/*/send_redirects
  • Yes this seems to work, instead of setting this for all interfaces I need to set it for the wifi interface specifically. Linux kernel bug?
    – Mark Koek
    Jan 12, 2016 at 14:50

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