On 01/04/2015 01:59 PM, Kevin Cozens wrote:
On 15-01-04 12:55 PM, James Knott wrote:
One thing I noticed recently was that my firewall, running Linux, was getting a MTU of 576 bytes, instead of the normal 1500 bytes. This was being set by the Rogers DHCP server (option 26). [snip] I have advised Rogers of this and the person I was speaking to agreed it should be 1500. Let's see if they fix it.
I am on Rogers and just checked my MTU setting after reading James' email. The ifconfig output reports an MTU of 1500. I didn't change any settings for DHCP. Rogers may have already fixed the problem.
I just tried some more testing with my notebook computer. It uses the KDE network manager and appears to ignore the DHCP MTU value. However, I can only ping with up to 1472 bytes when connected to the cable modem. I get the same when I tether to my smart phone (Rogers), but get the full 1500 to a local computer on my network. I do not use DHCP option 26 on my DHCP server. It also doesn't appear to be used when tethered to my smart phone.