[Bug 256393] Issue with recreation of ppp/tun interfaces

From: <bugzilla-noreply_at_freebsd.org>
Date: Sat, 05 Jun 2021 23:11:06 +0000
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=256393

--- Comment #26 from Rodney W. Grimes <rgrimes_at_FreeBSD.org> ---
(In reply to Eugene Grosbein from comment #25)
> Also, I do not understand how a router can deal without delivering traffic locally for its local IPs in many cases like running squid proxy or web/smtp server or even routinely running ping to check if distinct uplink is still alive.

You seem to not understand that traffic works just FINE without the loopback
route, packets sent locally to the local ip address of an interface are
delivered without any issue, the different is that the MTU used for the packets
well be the MTU of the ethernet/ppp/slip/whatever interface rather than the MTU
of the loopback device.

Further in your specific case of a ping check... that is near worthless to a
lo0 route as it can't tell when the carrier has dropped on an interface, and
infact this is one of the reasons I absolutely HATE this loopback route by the
kernel code and have ripped it out of my systems.

I think somehow you think that IP does not work correctly without the loopback
routes, that is a not the case.  I repeat, all the interface loopback routes
are not needed, the system functions fine without them. all be it with a 10x
packet count due to MTU delta for lo0 vs an ethernet.

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Received on Sat Jun 05 2021 - 23:11:06 UTC

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