AS199268 - LANCOM inzeniring racunalniskig sistemovPIRFC 4890 ✓RPKI ✓ 1/1ASPA -

AS overview

Test target: 2001:67c:1328:6::10 · lancom.si · address space: PI · prefixes announced: 1

prefix(es): 2001:67c:1328::/48

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

We probed 35 arbitrary IPv6 address(es) inside AS199268's announced prefix(es). No router inside the prefix responded. The deepest visible hop was 2a11:4142:2002::1 at hop 15 - that router answers ICMPv6 Echo. This is not in AS199268's announced prefix; operationally it's the AS-edge / peering interface (often on a SIX peering address or an upstream's /127 link). The traceroute boundary is the AS edge: ICMPv6 Time-Exceeded responses from anything inside this AS are filtered.

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 honored. Forged PTB accepted; next response shrunk. (ICMPv6 Echo + forged PTB)
• DE host (Düsseldorf): Type 2 honored. Forged PTB accepted; next response shrunk. (ICMPv6 Echo + forged PTB)
• 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). (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): inconclusive: no Echo Reply to 1300-byte probe. (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)

tracepath -6

 1?: [LOCALHOST]                        0.011ms pmtu 1500
 1:  _gateway                                              0.503ms 
 1:  _gateway                                              0.314ms 
 2:  2001:7f8:1e::4                                        0.568ms 
 3:  ts6-vix-mb.telekom.si                                27.841ms asymm  6 
 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
16:  no reply
17:  no reply
18:  no reply
19:  no reply
20:  no reply
21:  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)

tracepath -6

 1?: [LOCALHOST]                        0.026ms pmtu 1500
 1:  xe-0-0-13-178.gw01.ber01.as59645.net                  0.507ms 
 1:  xe-0-0-13-178.gw01.ber01.as59645.net                  0.519ms 
 2:  ae0-2453.cr10.ber01.lwlcom.net                        1.180ms 
 3:  ae0-10.cr10.ber03.lwlcom.net                          1.151ms 
 4:  ae0-15.cr11.dtm01.lwlcom.net                          9.175ms asymm  5 
 5:  ae0-10.cr10.dtm02.lwlcom.net                          8.772ms asymm  6 
 6:  ae0-20.cr10.dus04.lwlcom.net                          8.966ms asymm  5 
 7:  ae0-10.cr10.dus01.lwlcom.net                          8.856ms asymm  4 
 8:  ae6-60.cr10.ams01.lwlcom.net                         11.427ms asymm  5 
 9:  as5405.frys-ix.net                                   11.673ms 
10:  r7-ams1-nl.as5405.net                                32.421ms asymm 13 
11:  r7-fra1-de.as5405.net                                32.396ms asymm 12 
12:  r5-fra1-de.as5405.net                                32.379ms asymm 11 
13:  r2-vie1-at.as5405.net                                32.290ms asymm 10 
14:  r1-lju1-si.as5405.net                                32.339ms asymm  9 
15:  2a11:4142:2002::1                                    29.974ms asymm  7 
16:  no reply
17:  no reply
18:  no reply
19:  no reply
20:  no reply
21:  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)

tracepath -6

 1?: [LOCALHOST]                        0.026ms pmtu 1500
 1:  xe-0-0-12-142.gw01.dus01.as59645.net                  0.301ms 
 1:  xe-0-0-12-142.gw01.dus01.as59645.net                  0.233ms 
 2:  2001:7f8:9e::151d:0:1                                 0.442ms asymm  3 
 3:  r4-fra2-de.as5405.net                                19.674ms asymm 12 
 4:  r7-fra1-de.as5405.net                                19.883ms asymm 11 
 5:  r5-fra1-de.as5405.net                                19.717ms asymm 10 
 6:  r2-vie1-at.as5405.net                                19.684ms asymm  9 
 7:  r1-lju1-si.as5405.net                                19.710ms asymm  8 
 8:  2a11:4142:2002::1                                    16.910ms asymm  6 
 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
     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)

tracepath -6

 1?: [LOCALHOST]                        0.040ms pmtu 1500
 1:  2a00:8642:42::2                                       4.728ms 
 1:  2a00:8642:42::2                                       1.715ms 
 2:  no reply
 3:  2a00:1ca8:1::194                                      4.684ms 
 4:  2a03:3f40::10:41                                      4.350ms 
 5:  speed-ix.inter.link                                   5.080ms asymm  4 
 6:  r5-ams1-nl.as5405.net                                33.776ms asymm 15 
 7:  r7-ams1-nl.as5405.net                                30.751ms asymm 14 
 8:  r7-fra1-de.as5405.net                                32.573ms asymm 13 
 9:  r5-fra1-de.as5405.net                                31.532ms asymm 12 
10:  r2-vie1-at.as5405.net                                33.176ms asymm 11 
11:  r1-lju1-si.as5405.net                                32.554ms asymm 10 
12:  2a11:4142:2002::1                                    30.674ms asymm 10 
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
     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 3 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).

tracepath -6

 1?: [LOCALHOST]                        0.030ms pmtu 1500
 1:  karsolink-01.net.karsolink.com                        0.583ms 
 2:  2a12:d8c0:109f:121::a1                                0.650ms 
 3:  2a12:d8c0:101f:103::1                                 8.777ms 
 4:  interlink-as5405.mix-it.net                          17.230ms asymm  5 
 5:  r1-lju1-si.as5405.net                                15.900ms asymm  6 
 6:  2a11:4142:2002::1                                    20.838ms 
 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
     Too many hops: pmtu 1500
     Resume: pmtu 1500 

From SLO host (6connect)   openRFC 4890 ✗

filter likely at: (none) · min PMTU on path: 9000

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 9000
 1:  fw1-lju.6connect.com                                  0.581ms 
 1:  fw1-lju.6connect.com                                  0.493ms 
 2:  no reply
 3:  2a00:ee1:800:9::1                                     2.782ms 
 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
16:  no reply
17:  no reply
18:  no reply
19:  no reply
20:  no reply
21:  no reply
     Too many hops: pmtu 9000
     Resume: pmtu 9000 

From SLO host (T-2)   all blocked

filter likely at: past AS34779 (T-2-AS) · min PMTU on path: 1500

Path (traceroute + mtr + PTR)

tracepath -6

 1?: [LOCALHOST]                        0.026ms pmtu 1500
 1:  2a01:261:313:b814::1                                  0.628ms 
 1:  2a01:261:313:b814::1                                  0.642ms 
 2:  2a01:260:1::225                                       2.520ms 
 3:  2a01-260-1-1--9a.core6.t-2.net                        3.173ms 
 4:  2a01-260-1-1--c.core6.t-2.net                         4.190ms 
 5:  2a01:260:1:1::109                                     4.256ms 
 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
     Too many hops: pmtu 1500
     Resume: pmtu 1500