AS205243 - CLOUDNOW-AS CloudNowPARFC 4890 ✓RPKI ⚠ 2/3ASPA -

AS overview

Test target: 2a0b:adc0::2 · static prefix probe · address space: PA · prefixes announced: 3

prefix(es): 2a0b:adc0::/29, 2a0e:f2c0::/29, 2a0d:3c00::/29

VIX / AAIX / SAIX / TIROL-IX / ERA-IX peering

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

At least one router inside AS205243's announced prefix replied during the random-target probe. Hop(s): 2a0b:adc0::19. These are candidate targets for direct testing.

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

Type 2 honored. Forged ICMPv6 PTB (MTU=1280) was accepted by the destination's stack: the next 1500-byte Echo Reply arrived split into 2 fragments via the IPv6 Fragment Header.
method: ICMPv6 Echo + forged PTB, tested 2026-09-22T13:56:55Z

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]                        0.034ms pmtu 1500
 1:  _gateway                                             22.862ms 
 1:  _gateway                                              0.442ms 
 2:  sox-pn.sox.rs                                         0.429ms 
 3:  2001:7f8:1e:8::3d                                     0.601ms asymm  2 
 4:  ae8-930.RT.IRX.VIE.AT.retn.net                       12.943ms asymm  3 
 5:  2001:7f8:30:0:3:1000:20:5243                         13.273ms asymm  3 
 6:  2a0b:adc0::2                                         52.773ms reached
     Resume: pmtu 1500 hops 6 back 4 

From DE host (Berlin)   openRFC 4890 ✓

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

Path (traceroute + mtr + PTR)

tracepath -6

 1?: [LOCALHOST]                        0.023ms pmtu 1500
 1:  xe-0-0-13-178.gw01.ber01.as59645.net                  0.561ms 
 1:  xe-0-0-13-178.gw01.ber01.as59645.net                  0.548ms 
 2:  ae0-2453.cr10.ber01.lwlcom.net                        0.893ms 
 3:  ae0-40.cr10.muc02.lwlcom.net                         11.412ms 
 4:  ae0-10.cr10.muc01.lwlcom.net                         11.871ms 
 5:  2001:7f8:30:0:3:1000:20:5243                         17.757ms 
 6:  2a0b:adc0::2                                         17.923ms reached
     Resume: pmtu 1500 hops 6 back 6 

From DE host (Düsseldorf)   openRFC 4890 ✓

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

Path (traceroute + mtr + PTR)

tracepath -6

 1?: [LOCALHOST]                        0.015ms pmtu 1500
 1:  xe-0-0-12-142.gw01.dus01.as59645.net                  0.401ms 
 1:  xe-0-0-12-142.gw01.dus01.as59645.net                  0.424ms 
 2:  ae0-101.cr10.dus02.lwlcom.net                         0.621ms 
 3:  ae0-40.cr10.dus05.lwlcom.net                          3.584ms 
 4:  ae0-90.cr11.dus01.lwlcom.net                          0.813ms 
 5:  ae0-10.cr10.dus06.lwlcom.net                          0.679ms 
 6:  ae0-40.cr10.fra06.lwlcom.net                          4.060ms 
 7:  ae0-20.cr10.muc01.lwlcom.net                         14.934ms asymm  5 
 8:  2001:7f8:30:0:3:1000:20:5243                         20.616ms asymm  6 
 9:  2a0b:adc0::2                                         20.761ms reached
     Resume: pmtu 1500 hops 9 back 7 

From NL host (go6lab)   openRFC 4890 ✓

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

Path (traceroute + mtr + PTR)

Rate-limited ICMPv6: hop 7 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).

tracepath -6

 1?: [LOCALHOST]                        0.032ms pmtu 1500
 1:  2a00:8642:42::2                                       2.317ms 
 1:  2a00:8642:42::2                                       2.090ms 
 2:  gw.friends.steffann.nl                                3.521ms 
 3:  2a00:1ca8:1::194                                      4.924ms 
 4:  2a03:3f40::10:41                                      3.925ms 
 5:  2001:b28:3ff::1b1b:0:1                               28.683ms 
 6:  be2.core1.cph1.he.net                                27.510ms asymm  4 
 7:  be7.core3.ams1.he.net                                27.854ms asymm  3 
 8:  no reply
 9:  ams-ix.r06.nikh.ams.nl.nextlayer.net                 47.087ms asymm  8 
10:  2a01:190:15ff:66::3                                  39.919ms asymm 11 
11:  2a0b:adc0::2                                         39.596ms reached
     Resume: pmtu 1500 hops 11 back 11 

From ITA host (Karsolink)   openRFC 4890 ✓

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

Path (traceroute + mtr + PTR)

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

tracepath -6

 1?: [LOCALHOST]                        0.063ms pmtu 1500
 1:  no reply
 2:  no reply
 3:  2a12:d8c0:101f:6::1                                  10.245ms 
 4:  no reply
 5:  be47.core1.mil2.he.net                               11.280ms 
 6:  be1.core1.zrh2.he.net                                14.088ms 
 7:  no reply
 8:  be1.core3.zrh3.he.net                                15.895ms 
 9:  no reply
10:  no reply
11:  2a0b:adc0::19                                        17.910ms asymm  7 
12:  2a0b:adc0::2                                         18.090ms reached
     Resume: pmtu 1500 hops 12 back 7 

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]                        0.035ms pmtu 9000
 1:  fw1-lju.6connect.com                                  0.613ms 
 1:  fw1-lju.6connect.com                                  0.625ms 
 2:  no reply
 3:  no reply
 4:  2a00:ee0:1:15::2                                      1.663ms asymm  3 
 5:  2a00:ee0:1:10::2                                      3.394ms pmtu 1500
 5:  2a11:4142:2002::                                      1.243ms asymm  6 
 6:  r2-vie1-at.as5405.net                                 7.680ms asymm  8 
 7:  et9-4096.r2-vie2-at.as5405.net                        7.761ms asymm  8 
 8:  2001:7f8:30:0:3:1000:20:5243                          8.164ms asymm  4 
 9:  2a0b:adc0::2                                          8.140ms reached
     Resume: pmtu 1500 hops 9 back 5 

From SLO host (T-2)   openRFC 4890 ✓

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

Path (traceroute + mtr + PTR)

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

tracepath -6

 1?: [LOCALHOST]                        0.027ms pmtu 1500
 1:  2a01:261:313:b814::1                                  0.837ms 
 1:  no reply
 2:  2a01:260:1::225                                       4.503ms 
 3:  2a01-260-1-1--9a.core6.t-2.net                        3.092ms 
 4:  2a01-260-1-1--38.core6.t-2.net                        2.417ms asymm  3 
 5:  no reply
 6:  100ge0-0-0-31.core1.vie1.he.net                      12.378ms asymm  5 
 7:  vix-ip6-et-0-1-2-0-r60.inx.vie.at.nextlayer.net       9.731ms asymm  5 
 8:  2a0b:adc0::19                                        10.088ms asymm  6 
 9:  2a0b:adc0::2                                         10.368ms reached
     Resume: pmtu 1500 hops 9 back 6