First, this only seems to matter for Plain CoAP, not 'regular' CoAP. Though it seems like none of that messaging has been added yet.
Second, sudo echo "net.ipv4.ping_group_range=0 1000" >> /etc/sysctl.conf will give you an access denied. The correct way to do that would be echo "net.ipv4.ping_group_range=0 1000" | sudo tee -a /etc/sysctl.conf instead.
EDIT: I made pull request #51 based off of this one that makes both of these changes.
Two things:
First, this only seems to matter for Plain CoAP, not 'regular' CoAP. Though it seems like none of that messaging has been added yet.
Second,
sudo echo "net.ipv4.ping_group_range=0 1000" >> /etc/sysctl.confwill give you an access denied. The correct way to do that would beecho "net.ipv4.ping_group_range=0 1000" | sudo tee -a /etc/sysctl.confinstead.EDIT: I made pull request #51 based off of this one that makes both of these changes.