how to fix this error unknown option "--icmp-type"?

Muhammad Robi Rahman

12/9/23, 9:48 AM

I want to block ICMP ping request and I have followed syntax from tutorials, but get the same result:

error image

sudo iptables -A OUTPUT -p icmp --icmp-type echo-request -j DROP
iptables v1.8.7 (nf_tables) : unknown option "--icmp-type"
Try 'iptables -h' or 'iptables --help for more information.

Any help would be appreciated. Thank you.

494

1 + 1

networking

error-handling

steeldriver

12/9/23, 1:48 PM

Are you trying to do this on WSL by any chance?

Score:0

Ubuntu

matigo

12/9/23, 9:58 AM

Looking at the manual for iptables there is no --icmp-type option. That said, if you would like to block all ICMP requests, you can do this:

Open Terminal (if it's not already open)
Edit the sysctl.conf file with elevated permissions:
```
sudo {editor of choice} /etc/sysctl.conf
```
^{Note: Be sure to replace {editor of choice} with your preferred editor.}
Add the following line to the end of the file:
```
net.ipv4.icmp_echo_ignore_all = 1
```
Save the changes and exit the editor.
Apply the configuration change:
```
sysctl -p
```

Now the system will ignore all ICMP requests. This change will persist across reboots, too.

+ 1

steeldriver

12/9/23, 1:46 PM

The `--icmp-type` option is documented in the `iptables-extensions` man page I think ...

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