Package: traceroute Version: 1:2.1.0-2 Severity: normal When a router on the path returns ICMPv6 type 1 (Destination unreachable) code 6 (reject route to destination), traceroute fails to recognise that as an error condition and soldiers on with higher TTLs, thus giving the impression of a routing loop where there is none.
Probably traceroute should treat _all_ type 1 packets as an error condition and stop there, whether it knows about the code or not. $ traceroute6 2a0b:b880:1000::1 traceroute to 2a0b:b880:1000::1 (2a0b:b880:1000::1) from 2001:470:c82d:ff:56a0:50ff:fe85:3b43, 30 hops max, 24 byte packets 1 tikva.mamane.lu (2001:470:c82d:ff::1) 0,328 ms 0,305 ms 0,302 ms 2 tunnel336250.tunnel.tserv10.par1.ipv6.he.net (2001:470:1f12:c7::1) 16,034 ms 12,795 ms 13,55 ms 3 10ge7-3.core1.par2.he.net (2001:470:0:7b::1) 12,157 ms 12,981 ms 13,717 ms 4 100ge2-2.core1.fra1.he.net (2001:470:0:2d5::2) 22,788 ms 22,361 ms 22,879 ms 5 2001:7e8:0:1101::2 (2001:7e8:0:1101::2) 28,984 ms 25,824 ms 26,438 ms 6 2001:7e8:1:11fe::b (2001:7e8:1:11fe::b) 24,868 ms 26,235 ms 25,95 ms 7 2001:7e8:82e4:200::1 (2001:7e8:82e4:200::1) 51,211 ms 40,831 ms 28,758 ms 8 2001:7e8:8f03:10f::2 (2001:7e8:8f03:10f::2) 24,976 ms 25,688 ms 67,135 ms 9 2001:7e8:8f03:10f::2 (2001:7e8:8f03:10f::2) 48,039 ms 47,38 ms 47,983 ms 10 2001:7e8:8f03:10f::2 (2001:7e8:8f03:10f::2) 48,418 ms 47,022 ms 48,012 ms etc $ ping6 2a0b:b880:1000::1 PING 2a0b:b880:1000::1(2a0b:b880:1000::1) 56 data bytes >From 2001:7e8:8f03:10f::2: icmp_seq=1 Destination unreachable: Unknown code 6 >From 2001:7e8:8f03:10f::2: icmp_seq=2 Destination unreachable: Unknown code 6 >From 2001:7e8:8f03:10f::2: icmp_seq=3 Destination unreachable: Unknown code 6 -- System Information: Debian Release: 10.4 APT prefers stable APT policy: (500, 'stable'), (400, 'testing'), (200, 'unstable'), (1, 'experimental') Architecture: amd64 (x86_64) Kernel: Linux 4.19.0-8-amd64 (SMP w/8 CPU cores) Kernel taint flags: TAINT_WARN Locale: LANG=fr_LU.UTF-8, LC_CTYPE=fr_LU.UTF-8 (charmap=UTF-8), LANGUAGE=fr_LU.UTF-8 (charmap=UTF-8) Shell: /bin/sh linked to /bin/bash Init: systemd (via /run/systemd/system) LSM: AppArmor: enabled Versions of packages traceroute depends on: ii libc6 2.30-8 traceroute recommends no packages. traceroute suggests no packages. -- no debconf information
