AS47267 - RNIDS-AS Serbian National Internet Domain Registry Foundati…PI/PARFC 4890 ✓RPKI ✓ 5/5ASPA -

AS overview

Test target: 2001:67c:69c::59 · ns1.rnids.rs · address space: mixed · prefixes announced: 5

prefix(es): 2a0f:eb80::/44, 2a0f:eb80::/48, 2a0f:eb80::/32, 2001:67c:69c::/48, 2a0f:eb80:1::/48

SOX peering

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

At least one router inside AS47267's announced prefix replied during the random-target probe. Hop(s): 2a0f:eb80:400:0:91:199:17:244. 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:

• SRB host (SOX, Belgrade): Type 2 honored. Forged PTB accepted; next response shrunk. (ICMPv6 Echo + forged PTB)
• DE host (Berlin): Type 2 NOT honored. Forged PTB had no effect (filtered en route or stack ignored it). (ICMPv6 Echo + forged PTB)
• DE host (Düsseldorf): Type 2 NOT honored. Forged PTB had no effect (filtered en route or stack ignored it). (ICMPv6 Echo + forged PTB)
• NL host (go6lab): Type 2 NOT honored. Forged PTB had no effect (filtered en route or stack ignored it). (ICMPv6 Echo + forged PTB)
• ITA host (Karsolink): Type 2 NOT honored. Forged PTB had no effect (filtered en route or stack ignored it). (ICMPv6 Echo + forged PTB)
• SLO host (6connect): Type 2 NOT honored. Forged PTB had no effect (filtered en route or stack ignored it). (ICMPv6 Echo + forged PTB)
• SLO host (T-2): Type 2 honored. Forged PTB accepted; next response shrunk. (ICMPv6 Echo + forged PTB)

Why they disagree - path-asymmetric Type 2 filtering: Both vantages used the ICMPv6 Echo + forged-PTB method on the same destination IP, but reached different verdicts. The destination's stack is the same in both cases - so the difference is in the path: a transit AS on one route filters our forged Type 2 (or its return ICMPv6 carrying the embedded packet) while the other route delivers it intact. The vantage that says honored shows what the destination's stack actually does; the one that says not honored shows that the path between us and them drops Type 2.

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 2a01:261:313:b814:2a0:98ff:fe5b:13e4 or src host 2a06:d1c1:10b::cccc or src host 2a06:d1c1:10d::aaaa or src host 2a09:ab81::91 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 or src host 2a09:ab81::91 or src host 2a01:261:313:b814:2a0:98ff:fe5b:13e4 or src host 2a06:d1c1:10a::bbbb or src host 2a06:d1c1:10d::aaaa or src host 2a06:d1c1:10b::cccc)'

Multi-vantage path map

Every hop of all vantages’ traceroutes toward the target, drawn left→right, grouped into per-AS bubbles (a hop seen from several vantages is one shared bubble, so converging paths merge). It answers two questions per vantage — shown on each source bubble as echo ✓/⚠/✗ · trace ✓/✗: did the destination reply to ICMPv6 Echo (✓ honored, ⚠ replied but PTB not honored, ✗ no reply), and did the traceroute reach it. A line to the target is drawn only when that vantage got an echo reply — solid if the PTB was honored, dashed if not (reachable but a broken-PMTUD / RFC 4890 violation). The path depth still shows how far the traceroute itself got, and runs of unanswered (* *) hops collapse into one dashed “silent” bubble. Open full size ↗

• ● SRB host (SOX, Belgrade)
• ● DE host (Berlin)
• ● DE host (Düsseldorf)
• ● NL host (go6lab)
• ● ITA host (Karsolink)
• ● SLO host (6connect)
• ● SLO host (T-2)
• ── solid line = echo reply, PTB honored (clean reach)
• — — dashed line = echo reply but PTB not honored (RFC 4890 violation)
• no line = no echo reply (never reached)
• ◉ target: green = clean, amber = reachable-but-violation / unreachable
• ⚠ suspected drop AS
• ⋯ silent (unanswered) hops
• ● IXP hop

From SRB host (SOX, Belgrade)   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]                        0.011ms pmtu 1500
 1:  _gateway                                              0.658ms 
 1:  _gateway                                              0.493ms 
 2:  rnids.sox.rs                                          0.776ms 
 3:  no reply
 4:  no reply
 5:  no reply
 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
     Too many hops: pmtu 1500
     Resume: pmtu 1500 

From DE host (Berlin)   openRFC 4890 ✗

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

Path (traceroute + mtr + PTR)

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

tracepath -6

 1?: [LOCALHOST]                        0.029ms pmtu 1500
 1:  xe-0-0-13-178.gw01.ber01.as59645.net                  0.428ms 
 1:  xe-0-0-13-178.gw01.ber01.as59645.net                  0.391ms 
 2:  ae0-2453.cr10.ber01.lwlcom.net                        0.911ms 
 3:  ae0-150.cr10.fra01.lwlcom.net                        10.295ms asymm  7 
 4:  ae0-100.cr10.fra02.lwlcom.net                        10.526ms asymm  8 
 5:  ae0-10.cr10.fra06.lwlcom.net                         10.158ms asymm  7 
 6:  no reply
 7:  rnids.sox.rs                                         34.488ms asymm  8 
 8:  no reply
 9:  no reply
10:  no reply
11:  no reply
12:  no reply
13:  no reply
14:  no reply
15:  no reply
     Too many hops: pmtu 1500
     Resume: pmtu 1500 

From DE host (Düsseldorf)   openRFC 4890 ✗

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

Path (traceroute + mtr + PTR)

Rate-limited ICMPv6: hop 3, hop 5, hop 9 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).

tracepath -6

 1?: [LOCALHOST]                        0.033ms pmtu 1500
 1:  xe-0-0-12-142.gw01.dus01.as59645.net                  0.370ms 
 1:  xe-0-0-12-142.gw01.dus01.as59645.net                  0.211ms 
 2:  ipv6.decix-dusseldorf.core1.dus1.he.net               8.298ms asymm  3 
 3:  100ge0-0-0-18.core4.fra1.he.net                      13.908ms asymm  4 
 4:  be8.core1.prg1.he.net                                21.229ms asymm  5 
 5:  be3.core1.vie1.he.net                                18.289ms asymm  4 
 6:  e0-35.core2.bts1.he.net                              17.313ms asymm  5 
 7:  e0-36.core2.beg1.he.net                              24.340ms asymm  6 
 8:  rnids.sox.rs                                         24.269ms asymm  7 
 9:  no reply
10:  no reply
11:  no reply
12:  no reply
13:  no reply
14:  no reply
15:  no reply
     Too many hops: pmtu 1500
     Resume: pmtu 1500 

From NL host (go6lab)   openRFC 4890 ✗

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

Path (traceroute + mtr + PTR)

Rate-limited ICMPv6: hop 3, hop 4, hop 6, hop 10 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).

tracepath -6

 1?: [LOCALHOST]                        0.040ms pmtu 1500
 1:  2a00:8642:42::2                                       3.007ms 
 1:  2a00:8642:42::2                                       1.888ms 
 2:  gw.friends.steffann.nl                                4.068ms 
 3:  speed-ix.he.net                                       8.345ms 
 4:  be2.core4.fra1.he.net                                17.498ms 
 5:  be8.core1.prg1.he.net                                27.512ms 
 6:  be3.core1.vie1.he.net                                28.141ms 
 7:  e0-35.core2.bts1.he.net                              24.453ms 
 8:  e0-36.core2.beg1.he.net                              29.400ms 
 9:  rnids.sox.rs                                         38.377ms asymm  6 
10:  no reply
11:  no reply
12:  no reply
13:  no reply
14:  no reply
15:  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)

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

tracepath -6

 1?: [LOCALHOST]                        0.029ms pmtu 1500
 1:  karsolink-01.net.karsolink.com                        0.438ms 
 2:  2a12:d8c0:109f:121::a1                                0.607ms 
 3:  2a12:d8c0:101f:103::1                                 8.632ms 
 4:  no reply
 5:  100ge0-0-0-20.core1.vie1.he.net                      21.546ms 
 6:  e0-35.core2.bts1.he.net                              22.394ms 
 7:  e0-36.core2.beg1.he.net                              29.677ms 
 8:  rnids.sox.rs                                         26.881ms asymm  7 
 9:  no reply
10:  no reply
11:  no reply
12:  no reply
13:  no reply
14:  no reply
15:  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 9 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).

tracepath -6

 1?: [LOCALHOST]                        0.019ms pmtu 9000
 1:  fw1-lju.6connect.com                                  0.586ms 
 1:  fw1-lju.6connect.com                                  0.467ms 
 2:  ccr-to-fw-ccr1-gw-lju.6connect.com                    1.025ms 
 3:  2a03:a100:0:201:1::1                                  1.133ms 
 4:  2a03:a100:0:201:1::1                                  0.795ms pmtu 1500
 4:  e0-1.core1.lju1.he.net                                2.188ms 
 5:  100ge0-0-0-5.core1.vie1.he.net                        7.358ms 
 6:  e0-35.core2.bts1.he.net                              11.678ms 
 7:  e0-36.core2.beg1.he.net                              15.091ms 
 8:  rnids.sox.rs                                         15.186ms 
 9:  no reply
10:  no reply
11:  no reply
12:  no reply
13:  no reply
14:  no reply
15:  no reply
     Too many hops: pmtu 1500

From SLO host (T-2)   openRFC 4890 ✓

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

Path (traceroute + mtr + PTR)

Rate-limited ICMPv6: hop 10 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).

tracepath -6

 1?: [LOCALHOST]                        0.024ms pmtu 1500
 1:  2a01:261:313:b814::1                                  0.914ms 
 2:  2a01:260:1::225                                       2.766ms 
 3:  2a01-260-1-1--9a.core6.t-2.net                        2.644ms 
 4:  2a01-260-1-1--38.core6.t-2.net                        3.294ms asymm  3 
 5:  100ge0-0-0-31.core1.vie1.he.net                      12.241ms 
 6:  e0-35.core2.bts1.he.net                              11.556ms 
 7:  e0-36.core2.beg1.he.net                              19.064ms 
 8:  e0-36.core2.beg1.he.net                              19.511ms asymm  7 
 9:  rnids.sox.rs                                         18.479ms asymm  8 
10:  no reply
11:  no reply
12:  no reply
13:  no reply
14:  no reply
15:  no reply
     Too many hops: pmtu 1500
     Resume: pmtu 1500