Date: Sat, 19 Jun 2021 18:02:01 UTC
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=256681 --- Comment #4 from Zhenlei Huang <email@example.com> --- (In reply to Rodney W. Grimes from comment #3) Comparing to stable/12 and stable/11, I call the route is "expected". Spent hours to repeat this on previous releases. Prior to FreeBSD 8.0, upon adding IP address to interface, only the on-link prefix route will be created. As for /32 aliases, the prefix route is /32. For output routine, ip_output() will consult rtalloc() to "generate" the loopback route for local IP address and use it. From FreeBSD 8.0 to FreeBSD 12.2, the on-link prefix route will be created, as well as the loopback route for local IP address. See . From FreeBSD 13.0 and onward, due to significant rework of routing subsystem, route for the /32 aliases is treated specially. See . I reviewed the design of loopback route. If I understand correctly, the loopback route short cut the out path of packets those are destined for local, it directly forward it to local and bypass the physical interface. See . So in some cases, if the loopback route is disabled and the hardware/logical interface can not forward those packets destined for local, 'No route to host' should be generated. PS, there is a 'net.link.ether.inet.useloopback' sysctl tunable, it is default on, and controls whether installing a loopback route or not. This tunable existed at least since 4.11 and was removed from stable/11. See . : https://cgit.freebsd.org/src/commit/sys/netinet/in.c?h=stable/8&id=ebc90701ac6c1f814c5bd6f3e19f0113ebe06156 : https://reviews.freebsd.org/D28668 : https://cgit.freebsd.org/src/tree/sys/netinet/if_ether.c?h=stable/4#n109 : https://cgit.freebsd.org/src/commit/sys/netinet/if_ether.c?h=stable/11&id=b1b9dcae46803ae79255a9994584cb03d2a77048 -- You are receiving this mail because: You are on the CC list for the bug.