Forcing DF bit in ipv4

[rikkic]

Hi, I'm new to arch linux arm but am currently using a Cubox-i4pro for a project.
One of the specifications on this project is that the Don't Fragment (DF) flag be set on all outgoing packets. In fedora 20 I have found I can do this by disabling PMTU discovery. But the same command does work on the cubox.
$this->bbcode_second_pass_code('', 'echo -n 1 > /proc/sys/net/ipv4/ip_no_pmtu_disc')

Anyone have any advice on what to try next?

Any help is much appreciated!

[pepedog]

$this->bbcode_second_pass_code('', 'echo "net.ipv4.ip_no_pmtu_disc = 0" > /etc/sysctl.d/99-pmtu.conf')
Or something like that

[rikkic]

Hi thanks for your help, I looked into sysctl and found the command was:
$this->bbcode_second_pass_code('', 'sysctl -w net.ipv4.ip_no_pmtu_disc=1')
Much appreciated!

[pepedog]

If you want it on boot, putting it into a conf file in /etc/sysctl.d/ like I described would do it

[rikkic]

Hi,

I've just been monitoring my device on wireshark and have noticed that not all packets are sent with the DF bit, any chance you'd know of anywhere else where the DF bit can be forced to '1'?