On my wireless access card (madwifi) I recently started seeing issues with the mtu, whereby at each dhcp request the mtu was reset to 68. Downgrading to 3.0.14 fixes the problem, so this appears to be related to the recent mtu fix that went into 3.0.15. I'm assuming that this happens when there is no mtu option sent (as my server does not). Based on the error message (minimum legal MTU is 68), it suggests that the mtu is being set to a lower value (possibly 0) and then being upgraded to the minimum accepted ethernet mtu. This has also been reported by a separate user in bug 166921. Please let me know if there's any other info you'd like or further tests I can run... 5:) Reproducible: Always Steps to Reproduce: 1. dhcpcd ath0 Actual Results: Error, ath0: minimum legal MTU is 68 Expected Results: mtu isn't altered or is set to a reasonable value
A little bit of printf-ing turned up that the dhcp->mtu is set to 64 when the check in dhcp.c occurs.
Ok, so sadly it tuns out my router really did want an MTU of 64 (it's a little bit lousy), but Uber's come up with a patch worthy of his namesake, which sets an MTU high enough to allow most traffic to continue working regardless (including DHCP itself). I'm off to go change my DHCP server to a more reliable one... 5:)
I'll close this when a fix hits portage
Fixed in dhcpcd-3.0.16
