[GTALUG] Ubuntu -- Disabling Ping

Alvin Starr alvin at netvel.net
Wed Aug 29 22:03:52 EDT 2018


On 08/29/2018 09:54 PM, Jamon Camisso via talk wrote:
> On 29/08/18 21:44, Howard Gibson via talk wrote:
>>     I am playing with my hack Ubuntu machine, and I am sorting out
>> security. I want to disable ping.  This is a laptop, and I want to
>> document the application of aluminium foil.
>>
>>     The standard ping disabler is the following line...
>>
>> # echo 1 > /proc/sys/net/ipv4/icmp_echo_ignore_all
>>
>>     This works fine on my Fedora laptop.  On Ubuntu, I get...
> The # makes me think you are root on the Fedora laptop.
>
>> $ sudo echo 1 > /proc/sys/net/ipv4/icmp_echo_ignore_all
>> -bash: /proc/sys/net/ipv4/icmp_echo_ignore_all: Permission denied
> That's expected with a sudo echo > redirect invocation. The shell is
> doing redirection. sudo is invoking echo, the output of which is being
> redirected in your normal user's shell to a file that you do not have
> permission to write to.
>
> Try this if you want to go the sudo route:
>
> echo 1 |sudo tee /proc/sys/net/ipv4/icmp_echo_ignore_all
>
> That way tee is invoked with elevated privileges and writes its output
> to the file.
>
> Or you can become root like on your Fedora system and use echo 1 >...
>
you could also do the following:

sudo sysctl net.ipv4.icmp_echo_ignore_all=1

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