AS41427 - DatacenterPIRFC 4890 ✓RPKI -ASPA -

AS overview

Test target: 2001:678:cc8:2:8000:: · via IPv6 Hitlist (responsive) · address space: PI · prefixes announced: 1

prefix(es): 2001:678:cc8::/48

SIX peering

Random-IP probe (yarrp) into the AS' prefixes

At least one router inside AS41427's announced prefix replied during the random-target probe. Hop(s): 2001:678:cc8:ffff::5. These are candidate targets for direct testing.

ICMPv6 Type 2 (Packet Too Big) acceptance - active test

Vantage points disagree about Type 2 acceptance - transit ASes on one path may be filtering Type 2 even though the destination's stack accepts it on another path:

• NL host (go6lab): Type 2 honored. Forged PTB accepted; next response shrunk. (ICMPv6 Echo + forged PTB)
• ITA host (Karsolink): Type 2 NOT honored. Forged PTB had no effect (filtered en route or stack ignored it). (TLS handshake + forged PTB)
• SLO host (6connect): Type 2 honored. Forged PTB accepted; next response shrunk. (ICMPv6 Echo + forged PTB)

Why they disagree - different probe methods: These vantages picked different probe methods, so their verdicts are not directly comparable. The active test tries methods in order (icmp6-echo → dns-tcp → tls → http) and stops at the first that produces a definitive verdict; if the chosen method differs, the underlying evidence differs too. Most often this is because the path PMTU on one vantage is below 1500 B, so the natural Echo Reply is already fragmented and the icmp6-echo method falls through to a TCP-based one. This is largely a measurement artifact, not a destination-behaviour difference.

sudo tcpdump -i any -n -e 'icmp6 and ip6[40] = 2 and (src host 2607:fae0:a000::42 or src host 2a00:8642:42::75 or src host 2a12:d8c0:105a:9001::a154)'

sudo ip6tables -L INPUT -nv | grep -iE 'icmpv6|packet-too-big'
sudo nft list ruleset 2>/dev/null | grep -A1 'icmpv6'

sudo sysctl net.ipv6.conf.all.accept_redirects net.ipv4.ip_no_pmtu_disc net.ipv6.route.mtu_expires

sudo tcpdump -i any -n -e 'icmp6 and ip6[40] = 2 and (src host 2607:fae0:a000::42 or src host 2a00:8642:42::75 or src host 2a12:d8c0:105a:9001::a154)'

From NL host (go6lab)   openRFC 4890 ✓

filter likely at: (none) · min PMTU on path: 1500

Path (traceroute + mtr + PTR)

Rate-limited ICMPv6: hop 5, hop 6, hop 8, hop 9 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).

tracepath -6

 1?: [LOCALHOST]                        0.056ms pmtu 1500
 1:  2a00:8642:42::3                                       1.690ms 
 1:  2a00:8642:42::3                                       1.802ms 
 2:  gw.friends.steffann.nl                                2.543ms 
 3:  2a00:1ca8:1::194                                      3.249ms 
 4:  2a03:3f40::10:41                                      2.669ms 
 5:  2001:978:2:40::3:1                                    4.236ms 
 6:  no reply
 7:  be2950.ccr42.fra05.atlas.cogentco.com                11.983ms 
 8:  no reply
 9:  be9456.ccr82.vie01.atlas.cogentco.com                23.759ms 
10:  be7244.agr62.vie01.atlas.cogentco.com                23.440ms 
11:  be9461.rcr62.lju01.atlas.cogentco.com                29.728ms 
12:  be9462.nr61.b021176-0.lju01.atlas.cogentco.com       29.926ms 
13:  2001:978:2:39::6:2                                   29.665ms 
14:  2001:678:cc8:ffff::5                                 30.844ms 
15:  no reply
16:  no reply
17:  no reply
18:  no reply
19:  no reply
20:  no reply
21:  no reply
22:  no reply
23:  no reply
24:  no reply
     Too many hops: pmtu 1500
     Resume: pmtu 1500 

From ITA host (Karsolink)   openRFC 4890 ✗

filter likely at: (none) · min PMTU on path: 1500

Path (traceroute + mtr + PTR)

tracepath -6

 1?: [LOCALHOST]                        0.030ms pmtu 1500
 1:  karsolink-01.net.karsolink.com                        1.518ms 
 2:  2a12:d8c0:109f:121::a1                                1.098ms 
 3:  2a12:d8c0:101f:6::1                                  10.538ms 
 4:  2a03:b020:1:51::a                                    11.004ms 
 5:  2a03:b020::246                                       11.193ms asymm  6 
 6:  2001:978:2:2a::e7:1                                  11.661ms asymm  7 
 7:  be4918.agr62.mil02.atlas.cogentco.com                11.408ms asymm  8 
 8:  port-channel3336.ccr92.mil02.atlas.cogentco.com      13.991ms asymm  9 
 9:  no reply
10:  be9456.ccr82.vie01.atlas.cogentco.com                27.537ms asymm 11 
11:  be7244.agr62.vie01.atlas.cogentco.com                25.608ms asymm 12 
12:  be9461.rcr62.lju01.atlas.cogentco.com                31.839ms asymm 13 
13:  be3191.nr61.b021176-0.lju01.atlas.cogentco.com       32.095ms asymm 14 
14:  2001:978:2:39::6:2                                   29.196ms asymm  8 
15:  2001:678:cc8:ffff::5                                 32.823ms asymm  9 
16:  no reply
17:  no reply
18:  no reply
19:  no reply
20:  no reply
21:  no reply
22:  no reply
23:  no reply
24:  no reply
     Too many hops: pmtu 1500
     Resume: pmtu 1500 

From SLO host (6connect)   openRFC 4890 ✓

filter likely at: (none) · min PMTU on path: 1500

Path (traceroute + mtr + PTR)

Rate-limited ICMPv6: hop 3 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).

tracepath -6

 1?: [LOCALHOST]                        0.036ms pmtu 1500
 1:  fw1-lju.6connect.com                                  0.478ms 
 1:  fw1-lju.6connect.com                                  0.486ms 
 2:  no reply
 3:  2a03:a100:0:201:1::1                                  0.634ms 
 4:  six2.metronet.si                                      0.886ms 
 5:  2001:678:cc8:ffff::5                                  1.870ms 
 6:  no reply
 7:  no reply
 8:  no reply
 9:  no reply
10:  no reply
11:  no reply
12:  no reply
13:  no reply
14:  no reply
15:  no reply
16:  no reply
17:  no reply
18:  no reply
19:  no reply
20:  no reply
21:  no reply
22:  no reply
23:  no reply
24:  no reply
     Too many hops: pmtu 1500
     Resume: pmtu 1500