AS5602 - AS-IRIDEOS-KP Retelit Digital ServicesPI/PARFC 4890 ✗RPKI -ASPA -

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AS overview

Test target: 2001:1450::1 · static prefix probe · address space: mixed · prefixes announced: 1

prefix(es): 2001:1450::/32

Targets & per-vantage-point probe results (1 target(s) across 7 vantage point(s))

Source codes (hover any badge for full description): CUR=curated · NS/SOA/MX=DNS records · SPF=SPF TXT · DRV=holder-derived (www, ns1, mail, gw, …) · ATL=RIPE Atlas · PDB=PeeringDB · WHOIS=RIPE whois · RDAP=RIPE RDAP · HIT=IPv6 Hitlist · RTR=in-prefix path hop (router) · PRB=static prefix probe · SYN=synthetic prefix::1 fallback

Target IP / hostnameSourceSRB host (SOX, Belgrade)DE host (Berlin)DE host (Düsseldorf)NL host (go6lab)ITA host (Karsolink)SLO host (6connect)SLO host (T-2)
ping1500B:80:443reachedping1500B:80:443reachedping1500B:80:443reachedping1500B:80:443reachedping1500B:80:443reachedping1500B:80:443reachedping1500B:80:443reached
2001:1450::1prbrefusedrefusedrefusedrefusedrefusedrefused??refusedrefusedrefusedrefusedrefusedrefused-

RPKI & ASPA

0 of 1 prefix(es) covered by a valid ROA, 1 not-found.

PrefixRPKI stateReasonCovering VRP(s)
2001:1450::/32- not-foundno covering VRP

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

At least one router inside AS5602's announced prefix replied during the random-target probe. Hop(s): 2001:1450::106, 2001:1450::119, 2001:1450::13a, 2001:1450::13d, 2001:1450::1a5. These are candidate targets for direct testing.

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

Type 2 not honored. Forged ICMPv6 PTB (MTU=1280) had no effect: the next 1500-byte Echo Reply still arrived whole (1460 B, no Fragment Header). PMTUD does not work toward this address from us.
method: ICMPv6 Echo + forged PTB, tested 2026-09-23T11:59:25Z

Failure detail - what to grep in your logs
vantageour sourceyour targetmethodresulttested (UTC)
belgrade2a09:ab81::912001:1450::1icmp6-echonot_honored2026-09-23T11:59:25Z
berlin2a06:d1c1:10b::cccc2001:1450::1icmp6-echonot_honored2026-09-23T11:59:25Z
duseldorf2a06:d1c1:10d::aaaa2001:1450::1icmp6-echonot_honored2026-09-23T11:59:24Z
go6lab2a00:8642:42::752001:1450::1icmp6-echonot_honored2026-09-23T11:59:48Z
karsolink2a12:d8c0:105a:9001::a1542001:1450::1icmp6-echonot_honored2026-09-23T11:59:26Z
odin2607:fae0:a000::422001:1450::1icmp6-echonot_honored2026-09-23T11:59:24Z
t22a01:261:313:b814:2a0:98ff:fe5b:13e42001:1450::1icmp6-echonot_honored2026-09-23T11:59:24Z

Attempt log (belgrade):

  1. icmp6-echonot_honored (reply shrank 1460→1460 B)
  2. dns-tcpno_tcp: connect failed: [Errno 111] Connection refused
  3. tlsno_tcp: TLS connect failed
  4. httpno_tcp: tcp/80 not open

Attempt log (berlin):

  1. icmp6-echonot_honored (reply shrank 1460→1460 B)
  2. dns-tcpno_tcp: connect failed: [Errno 111] Connection refused
  3. tlsno_tcp: TLS connect failed
  4. httpno_tcp: tcp/80 not open

Attempt log (duseldorf):

  1. icmp6-echonot_honored (reply shrank 1460→1460 B)
  2. dns-tcpno_tcp: connect failed: [Errno 111] Connection refused
  3. tlsno_tcp: TLS connect failed
  4. httpno_tcp: tcp/80 not open

Attempt log (go6lab):

  1. icmp6-echonot_honored (reply shrank 1460→1460 B)
  2. dns-tcpno_tcp: connect failed: timed out
  3. tlsno_tcp: TLS connect failed
  4. httpno_tcp: tcp/80 not open

Attempt log (karsolink):

  1. icmp6-echonot_honored (reply shrank 1460→1460 B)
  2. dns-tcpno_tcp: connect failed: [Errno 111] Connection refused
  3. tlsno_tcp: TLS connect failed
  4. httpno_tcp: tcp/80 not open

Attempt log (odin):

  1. icmp6-echonot_honored (reply shrank 1460→1460 B)
  2. dns-tcpno_tcp: connect failed: [Errno 111] Connection refused
  3. tlsno_tcp: TLS connect failed
  4. httpno_tcp: tcp/80 not open

Attempt log (t2):

  1. icmp6-echonot_honored (reply shrank 1460→1460 B)
  2. dns-tcpno_tcp: connect failed: [Errno 111] Connection refused
  3. tlsno_tcp: TLS connect failed
  4. httpno_tcp: tcp/80 not open

To match the corresponding ICMPv6 packet on your side (host firewall, AS edge, or transit tap), look for our PTBs around the timestamps above:

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)'

If you see our PTBs arriving but the destination's TCP/Echo flow does not shrink, the drop is in the destination kernel (cause 3 below). If you don't see them at all, drop is upstream of you (cause 2). If you only see them from some of our source IPs but not others, the drop is path-asymmetric - at least one transit on the differing route is filtering.

What does "Type 2 not honored" actually mean? - click to expand

What this test does

Using the icmp6-echo method, we send a 1500-byte ICMPv6 Echo Request, then a forged ICMPv6 Type 2 (Packet Too Big) declaring path MTU=1280, and observe whether the next Echo Reply arrives split into IPv6 fragments. RFC 4890 requires hosts and intermediate networks not to filter ICMPv6 Type 2; the destination's TCP/UDP stack must act on a received PTB by lowering its Path MTU cache for that destination, which makes subsequent segments smaller.

What we measured

The TCP segment size your server emitted before our forged Type 2 was 1460 B; after, it was 1460 B. No change. RFC 4890 ("Type 2 messages MUST NOT be filtered") expects subsequent segments to shrink to fit a Path MTU of 1280 B.

Three plausible causes

  1. Your host firewall is dropping ICMPv6 Type 2 inbound. Many default firewall rule sets only allow Echo Request/Reply and Neighbor Discovery, silently dropping all other ICMPv6 types - including Packet Too Big.
  2. An upstream / transit network is dropping ICMPv6 Type 2 before it reaches you. Some transit ASes filter ICMPv6 messages other than Echo at the edge. The forged PTB never arrives, so your stack never has a chance to act on it.
  3. Your kernel is ignoring the PTB. Linux / BSD stacks normally accept ICMPv6 PTB and update the route cache, but a few sysctls (or a hardened kernel) can be configured to ignore PMTU updates - typically as part of an over-aggressive anti-spoofing or uRPF policy.

How to check & fix (Linux examples)

1. Confirm Type 2 is not blocked at the host firewall:

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

If you see rules dropping ICMPv6 unconditionally, change them to permit at least icmpv6 type packet-too-big (and destination-unreachable, time-exceeded, parameter-problem per RFC 4890).

2. Confirm the kernel accepts incoming PTB:

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

The defaults (accept_redirects=1, ip_no_pmtu_disc=0) are the right values for honoring PTB.

3. Live trace: while we have an open TCP flow with a small MSS (we run our test from 2607:fae0:a000::42 on odin, 2a00:8642:42::75 on go6lab, 2a12:d8c0:105a:9001::a154 on karsolink, 2a09:ab81::91 on belgrade, 2a01:261:313:b814:2a0:98ff:fe5b:13e4 on t2, 2a06:d1c1:10a::bbbb on amsterdam, 2a06:d1c1:10d::aaaa on duseldorf and 2a06:d1c1:10b::cccc on berlin), watch for our forged Type 2 arriving on your interface:

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)'

If you see our PTBs arriving but TCP segments still stay big, the drop is in your kernel or NIC offload (cause 3). If you don't see them at all, the drop is upstream of you (cause 2) - ask your upstream(s) to permit ICMPv6 Type 2.

4. If your test target above (2026-09-23T11:59:25Z) is a host that you don't own (e.g. a third-party DNS / TLS server you happen to operate prefixes for), the verdict reflects that specific host's behaviour - try the test against a server you do own and we'll happily re-run.

RFC 4890 references: §4.3.1 (Packet Too Big - MUST NOT be dropped), and RFC 8201 for the broader PMTUD requirement.

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 ↗

multi-vantage path diagram for AS5602

From SRB host (SOX, Belgrade)   openRFC 4890 ✗

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

4/4
Echo small (56B) 26.8ms
4/4
Echo 1500B (DF) 26.8ms
yes
Type 1 dest-unreach
443,80
TCP responds on

Path (traceroute + mtr + PTR)

#IP / PTRRTTmtr lossASAS holder
12a09:ab81::10.3ms0%*AS60733PERKE-NET - ZORAN PEROVIC trading as Agencija Perke.NET, RS
2sox-pn.sox.rs
2001:7f8:1e:8::3a
0.4ms0%AS13004SOX - Serbian Open Exchange DOO, RS
3e0-33.core2.beg1.he.net
2001:470:1:6e5::1
1.1ms10%AS6939HURRICANE - Hurricane Electric LLC, US
4e0-34.core2.bts1.he.net
2001:470:0:33f::2
8.2ms10%AS6939HURRICANE - Hurricane Electric LLC, US
5100ge0-0-0-2.core1.vie1.he.net
2001:470:0:412::1
11.9ms10%AS6939HURRICANE - Hurricane Electric LLC, US
6*---
7retelit.topix.it
2001:7f8:23:ffff::50
26.5ms0%-NA
82a02:7d8::226.6ms0%AS3302AS-RETELIT-IRIDEOS - Retelit Digital Services S.p.A., IT
92a02:7d8:0:f::ae26.2ms0%AS3302AS-RETELIT-IRIDEOS - Retelit Digital Services S.p.A., IT
102001:1450::1a526.9ms60%AS5602AS-IRIDEOS-KP - Retelit Digital Services S.p.A., IT
112001:1450::127.4ms0%AS5602AS-IRIDEOS-KP - Retelit Digital Services S.p.A., IT

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

tracepath -6

 1?: [LOCALHOST]                        0.033ms pmtu 1500
 1:  _gateway                                              0.616ms 
 1:  _gateway                                              0.450ms 
 2:  sox-pn.sox.rs                                         0.794ms 
 3:  e0-33.core2.beg1.he.net                               1.603ms 
 4:  e0-34.core2.bts1.he.net                               8.936ms 
 5:  100ge0-0-0-2.core1.vie1.he.net                       11.137ms 
 6:  no reply
 7:  irideos.minap.it                                     27.043ms asymm  6 
 8:  2a02:7d8::2                                          26.737ms asymm  6 
 9:  2a02:7d8:0:f::ae                                     26.401ms asymm  6 
10:  no reply
11:  2001:1450::1                                         27.331ms reached
     Resume: pmtu 1500 hops 11 back 6 

From DE host (Berlin)   openRFC 4890 ✗

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

4/4
Echo small (56B) 21.4ms
4/4
Echo 1500B (DF) 21.5ms
yes
Type 1 dest-unreach
443,80
TCP responds on

Path (traceroute + mtr + PTR)

#IP / PTRRTTmtr lossASAS holder
1xe-0-0-13-178.gw01.ber01.as59645.net
2a06:d1c1:100:b::1
0.2ms0%*AS59645WYBT-NET - Tobias Fiebig, DE
2ae0-2453.cr10.ber01.lwlcom.net
2a06:d1c0::dead:beef:1c02
0.6ms0%*AS59645WYBT-NET - Tobias Fiebig, DE
3ae0-150.cr10.fra01.lwlcom.net
2a00:c380:b200:230::174
9.8ms0%AS50629LWLCOM - LWLcom GmbH, DE
4ae0-20.cr10.fra07.lwlcom.net
2a00:c380:b200:230::31
10.2ms0%AS50629LWLCOM - LWLcom GmbH, DE
5*-60%-
6lo0.0.edge1.Milan1.level3.net
2001:4c08::b8
1933.8ms0%AS3356LEVEL3 - Level 3 Parent, LLC, US
72001:1900:5:2:2::64da21.2ms10%AS3356LEVEL3 - Level 3 Parent, LLC, US
82a02:7d8::221.5ms0%AS3302AS-RETELIT-IRIDEOS - Retelit Digital Services S.p.A., IT
92a02:7d8:0:f::ae20.8ms0%AS3302AS-RETELIT-IRIDEOS - Retelit Digital Services S.p.A., IT
10*---
112001:1450::121.9ms0%AS5602AS-IRIDEOS-KP - Retelit Digital Services S.p.A., IT

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

tracepath -6

 1?: [LOCALHOST]                        0.020ms pmtu 1500
 1:  xe-0-0-13-178.gw01.ber01.as59645.net                  0.541ms 
 1:  xe-0-0-13-178.gw01.ber01.as59645.net                  0.477ms 
 2:  ae0-2453.cr10.ber01.lwlcom.net                        1.026ms 
 3:  ae0-150.cr10.fra01.lwlcom.net                        10.556ms asymm  7 
 4:  ae0-20.cr10.fra07.lwlcom.net                         10.402ms asymm  6 
 5:  no reply
 6:  lo0.0.edge1.Milan1.level3.net                        24.138ms asymm  8 
 7:  2001:1900:5:2:2::64da                                21.783ms asymm 10 
 8:  2a02:7d8::2                                          21.716ms asymm 11 
 9:  2a02:7d8:0:f::ae                                     21.125ms asymm 11 
10:  no reply
11:  2001:1450::1                                         22.058ms reached
     Resume: pmtu 1500 hops 11 back 11 

From DE host (Düsseldorf)   openRFC 4890 ✗

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

4/4
Echo small (56B) 20.8ms
4/4
Echo 1500B (DF) 20.9ms
yes
Type 1 dest-unreach
443,80
TCP responds on

Path (traceroute + mtr + PTR)

#IP / PTRRTTmtr lossASAS holder
1xe-0-0-12-142.gw01.dus01.as59645.net
2a06:d1c1:100:d::1
0.1ms0%*AS59645WYBT-NET - Tobias Fiebig, DE
2eth1-0-12-h5594.edge5-dus1.bb.wiit.network
2001:4ba0:92f4:3::1
10.8ms0%AS24961MYLOC-AS - WIIT AG, DE
3lag10-h5f01.agr4-dus1.bb.wiit.network
2001:4ba0:ffe9:7c::1
9.4ms0%AS24961MYLOC-AS - WIIT AG, DE
4lag11.core3-dus1.bb.wiit.network
2001:4ba0:ffe9:115::3
0.2ms0%AS24961MYLOC-AS - WIIT AG, DE
5lag0-vl1011.core1-fra-ix.bb.wiit.network
2001:4ba0:ffe9:8a::2
4.4ms0%AS24961MYLOC-AS - WIIT AG, DE
6lag0-vl1001.core1-nbg-ncd.bb.wiit.network
2001:4ba0:ffe9:103e::1
6.8ms0%AS24961MYLOC-AS - WIIT AG, DE
7lag0-vl6.core2-nbg-ncd.bb.wiit.network
2001:4ba0:ffe9:103b::1
7.6ms0%AS24961MYLOC-AS - WIIT AG, DE
82001:4ba0:ffe9:b89.5ms0%-
9lag0-vl1009.core1-muc-eq3.bb.wiit.network
2001:4ba0:ffe9:a7::1
9.6ms0%AS24961MYLOC-AS - WIIT AG, DE
10lag0-vl1001.core1-pda-vsix.bb.wiit.network
2001:4ba0:ffe9:da::2
20.4ms0%AS24961MYLOC-AS - WIIT AG, DE
11lag0-vl1001.core1-mil-mix.bb.wiit.network
2001:4ba0:ffe9:db::2
20.3ms0%AS24961MYLOC-AS - WIIT AG, DE
12lag0-vl5.core3-mil-irid.bb.wiit.network
2001:4ba0:ffe9:9a::2
20.0ms0%AS24961MYLOC-AS - WIIT AG, DE
13*---
142a02:7d8::221.0ms0%AS3302AS-RETELIT-IRIDEOS - Retelit Digital Services S.p.A., IT
152a02:7d8:0:f::ae20.1ms0%AS3302AS-RETELIT-IRIDEOS - Retelit Digital Services S.p.A., IT
162001:1450::1a520.7ms30%AS5602AS-IRIDEOS-KP - Retelit Digital Services S.p.A., IT
172001:1450::121.3ms0%AS5602AS-IRIDEOS-KP - Retelit Digital Services S.p.A., IT

Rate-limited ICMPv6: hop 16 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).

tracepath -6

 1?: [LOCALHOST]                        0.015ms pmtu 1500
 1:  xe-0-0-12-142.gw01.dus01.as59645.net                  0.304ms 
 1:  xe-0-0-12-142.gw01.dus01.as59645.net                  0.288ms 
 2:  eth1-0-12-h5594.edge5-dus1.bb.wiit.network           24.062ms 
 3:  no reply
 4:  lag11.core3-dus1.bb.wiit.network                      0.396ms 
 5:  lag0-vl1011.core1-fra-ix.bb.wiit.network              4.408ms 
 6:  lag0-vl1001.core1-nbg-ncd.bb.wiit.network             6.754ms 
 7:  lag0-vl6.core2-nbg-ncd.bb.wiit.network                6.890ms 
 8:  lag0-vl1006.core2-muc2.bb.wiit.network                9.493ms 
 9:  lag0-vl1009.core1-muc-eq3.bb.wiit.network             9.939ms 
10:  lag0-vl1001.core1-pda-vsix.bb.wiit.network           20.197ms 
11:  lag0-vl1001.core1-mil-mix.bb.wiit.network            20.401ms asymm  9 
12:  lag0-vl5.core3-mil-irid.bb.wiit.network              20.222ms asymm  8 
13:  no reply
14:  2a02:7d8::2                                          20.791ms asymm 10 
15:  2a02:7d8:0:f::ae                                     20.402ms asymm 10 
16:  no reply
17:  2001:1450::1                                         21.501ms reached
     Resume: pmtu 1500 hops 17 back 10 

From NL host (go6lab)   openRFC 4890 ✗

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

4/4
Echo small (56B) 46.8ms
4/4
Echo 1500B (DF) 47.5ms
yes
Type 1 dest-unreach
-
TCP responds on

Path (traceroute + mtr + PTR)

#IP / PTRRTTmtr lossASAS holder
12a00:8642:42::21.8ms0%AS203993GNA-DC1-AS - S.J.M. Steffann, NL
2*-0%*-
32a00:1ca8:1::1947.4ms0%AS50673Serverius-as - Serverius Holding B.V., NL
42a03:3f40::10:419.8ms0%AS50673Serverius-as - Serverius Holding B.V., NL
52001:978:2:40::3:14.1ms0%AS174COGENT-174 - Cogent Communications, LLC, US
6be3457.ccr41.ams03.atlas.cogentco.com
2001:550:0:1000::8275:109
6.0ms0%AS174COGENT-174 - Cogent Communications, LLC, US
7be2950.ccr42.fra05.atlas.cogentco.com
2001:550:0:1000::9a36:482a
13.1ms0%AS174COGENT-174 - Cogent Communications, LLC, US
8be7944.ccr22.muc03.atlas.cogentco.com
2001:550:0:1000::9a36:4b61
18.1ms0%AS174COGENT-174 - Cogent Communications, LLC, US
9port-channel5891.ccr91.mil02.atlas.cogentco.com
2001:550:0:1000::9a36:3db5
27.1ms0%AS174COGENT-174 - Cogent Communications, LLC, US
10be2434.rcr71.vce01.atlas.cogentco.com
2001:550:0:1000::9a36:279e
28.9ms0%AS174COGENT-174 - Cogent Communications, LLC, US
11be2440.rcr51.rom01.atlas.cogentco.com
2001:550:0:1000::9a36:3832
36.3ms0%AS174COGENT-174 - Cogent Communications, LLC, US
122001:978:2:11::b:237.7ms20%AS174COGENT-174 - Cogent Communications, LLC, US
13*---
14*---
15*---
162a02:7d8::248.9ms0%AS3302AS-RETELIT-IRIDEOS - Retelit Digital Services S.p.A., IT
172a02:7d8:0:f::ae46.6ms0%AS3302AS-RETELIT-IRIDEOS - Retelit Digital Services S.p.A., IT
18*-40%-
192001:1450::151.9ms0%AS5602AS-IRIDEOS-KP - Retelit Digital Services S.p.A., IT

Rate-limited ICMPv6: hop 12, hop 18 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).

tracepath -6

 1?: [LOCALHOST]                        0.070ms pmtu 1500
 1:  2a00:8642:42::2                                       4.233ms 
 1:  2a00:8642:42::2                                       3.394ms 
 2:  no reply
 3:  2a00:1ca8:1::194                                     19.949ms 
 4:  2a03:3f40::10:41                                      7.114ms 
 5:  2001:978:2:40::3:1                                   10.119ms 
 6:  be3458.ccr42.ams03.atlas.cogentco.com                 9.996ms 
 7:  be3343.ccr41.fra05.atlas.cogentco.com                16.006ms 
 8:  be7944.ccr22.muc03.atlas.cogentco.com                20.442ms 
 9:  port-channel5892.ccr92.mil02.atlas.cogentco.com      32.842ms 
10:  be2434.rcr71.vce01.atlas.cogentco.com                34.352ms 
11:  be2440.rcr51.rom01.atlas.cogentco.com                43.306ms 
12:  2001:978:2:11::b:2                                   38.244ms 
13:  no reply
14:  no reply
15:  no reply
16:  2a02:7d8::2                                          45.913ms 
17:  2a02:7d8:0:f::ae                                     47.573ms asymm 16 
18:  2001:1450::1a5                                       45.544ms asymm 16 
19:  2001:1450::1                                         45.562ms reached
     Resume: pmtu 1500 hops 19 back 16 

From ITA host (Karsolink)   echo onlyRFC 4890 ✗

filter likely at: destination AS5602 (AS-IRIDEOS-KP) · min PMTU on path: 1500

4/4
Echo small (56B) 9.0ms
0/4
Echo 1500B (DF) -
yes
Type 1 dest-unreach
443,80
TCP responds on

Path (traceroute + mtr + PTR)

#IP / PTRRTTmtr lossASAS holder
1*---
22a12:d8c0:109f:121::a10.3ms0%*AS204471KARSOLINK - 2S Computers SRL, IT
32a12:d8c0:101f:103::18.5ms-AS204471KARSOLINK - 2S Computers SRL, IT
4irideos.minap.it
2001:7f8:c5::a500:3302:1
31.2ms0%AS3302IRIDEOS S.p.A.
52a02:7d8::27.6ms0%AS3302AS-RETELIT-IRIDEOS - Retelit Digital Services S.p.A., IT
62a02:7d8:0:f::ae8.2ms0%AS3302AS-RETELIT-IRIDEOS - Retelit Digital Services S.p.A., IT
72001:1450::1a59.2ms0%AS5602AS-IRIDEOS-KP - Retelit Digital Services S.p.A., IT
82001:1450::18.4ms0%AS5602AS-IRIDEOS-KP - Retelit Digital Services S.p.A., IT

tracepath -6

 1?: [LOCALHOST]                        0.030ms pmtu 1500
 1:  no reply
 2:  2a12:d8c0:109f:121::a1                                0.480ms 
 3:  2a12:d8c0:109f:106::a2                                3.437ms 
 4:  retelit.topix.it                                      8.127ms 
 5:  2a02:7d8::2                                           7.934ms 
 6:  2a02:7d8:0:f::ae                                      8.664ms asymm  5 
 7:  2001:1450::1a5                                        9.939ms asymm  5 
 8:  2001:1450::1                                         10.130ms reached
     Resume: pmtu 1500 hops 8 back 5 

From SLO host (6connect)   echo onlyRFC 4890 ✗

filter likely at: destination AS5602 (AS-IRIDEOS-KP) · min PMTU on path: 1500

4/4
Echo small (56B) 12.6ms
0/4
Echo 1500B (DF) -
yes
Type 1 dest-unreach
443,80
TCP responds on

Path (traceroute + mtr + PTR)

#IP / PTRRTTmtr lossASAS holder
1fw1-lju.6connect.com
2607:fae0:a000::2
0.3ms0%*AS80386CONNECT - 6connect, Inc., US
2ccr-to-fw-ccr1-gw-lju.6connect.com
2607:fae0:a000:2::2
0.7ms-AS80386CONNECT - 6connect, Inc., US
32a03:a100:0:201:1::10.8ms10%AS56635XENYA - XENYA inzeniring, proizvodnja in trgovina, d.o.o. Ljubljana, SI
4e0-1.core1.lju1.he.net
2001:470:1:5be::1
2.5ms50%AS6939HURRICANE - Hurricane Electric LLC, US
5*---
6port-channel1.core1.zag2.he.net
2001:470:0:2ea::2
4.0ms80%AS6939HURRICANE - Hurricane Electric LLC, US
7*---
8irideos.minap.it
2001:7f8:c5::a500:3302:1
55.2ms0%AS3302IRIDEOS S.p.A.
92a02:7d8::212.8ms0%AS3302AS-RETELIT-IRIDEOS - Retelit Digital Services S.p.A., IT
102a02:7d8:0:f::ae12.3ms0%AS3302AS-RETELIT-IRIDEOS - Retelit Digital Services S.p.A., IT
112001:1450::1a513.2ms0%AS5602AS-IRIDEOS-KP - Retelit Digital Services S.p.A., IT
122001:1450::113.3ms0%AS5602AS-IRIDEOS-KP - Retelit Digital Services S.p.A., IT

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

tracepath -6

 1?: [LOCALHOST]                        0.017ms pmtu 9000
 1:  fw1-lju.6connect.com                                  0.716ms 
 1:  fw1-lju.6connect.com                                  0.552ms 
 2:  no reply
 3:  2a03:a100:0:201:1::1                                  0.913ms 
 4:  2a03:a100:0:201:1::1                                  0.925ms pmtu 1500
 4:  no reply
 5:  no reply
 6:  port-channel1.core1.zag2.he.net                       4.281ms 
 7:  no reply
 8:  retelit.topix.it                                     12.811ms 
 9:  2a02:7d8::2                                          13.307ms 
10:  2a02:7d8:0:f::ae                                     12.407ms asymm  9 
11:  2001:1450::1a5                                       12.887ms asymm  9 
12:  2001:1450::1                                         13.483ms reached
     Resume: pmtu 1500 hops 12 back 9 

From SLO host (T-2)   openRFC 4890 ✗

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

4/4
Echo small (56B) 32.9ms
4/4
Echo 1500B (DF) 32.7ms
yes
Type 1 dest-unreach
443,80
TCP responds on

Path (traceroute + mtr + PTR)

#IP / PTRRTTmtr lossASAS holder
1*---
22a01:260:1::2251.6ms0%*AS34779T-2-AS - T-2, d.o.o., SI
32a01-260-1-1--9a.core6.t-2.net
2a01:260:1:1::9a
2.8ms0%*AS34779T-2-AS - T-2, d.o.o., SI
4hurricane-electric.nikhef.nlsix.net
2001:7f8:13::a500:6939:1
34.5ms0%-NA
5hurricane-electric.nikhef.nlsix.net
2001:7f8:13::a500:6939:1
34.3ms0%-NA
6be3.core4.fra1.he.net
2001:470:e:5a::2
39.3ms30%AS6939HURRICANE - Hurricane Electric LLC, US
7be3.core4.fra1.he.net
2001:470:e:5a::2
37.4ms0%AS6939HURRICANE - Hurricane Electric LLC, US
8be10.core1.zrh2.he.net
2001:470:e:153::2
44.7ms0%AS6939HURRICANE - Hurricane Electric LLC, US
9be1.core1.mil2.he.net
2001:470:e:dd::1
35.4ms-AS6939HURRICANE - Hurricane Electric LLC, US
10retelit.topix.it
2001:7f8:23:ffff::50
33.9ms60%-NA
112a02:7d8::245.0ms0%AS3302AS-RETELIT-IRIDEOS - Retelit Digital Services S.p.A., IT
122a02:7d8:0:f::ae44.8ms0%AS3302AS-RETELIT-IRIDEOS - Retelit Digital Services S.p.A., IT
132a02:7d8:0:f::ae42.9ms-AS3302AS-RETELIT-IRIDEOS - Retelit Digital Services S.p.A., IT
142001:1450::1a546.3ms0%AS5602AS-IRIDEOS-KP - Retelit Digital Services S.p.A., IT

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

tracepath -6

 1?: [LOCALHOST]                        0.027ms pmtu 1500
 1:  no reply
 2:  2a01:260:1::225                                       2.395ms 
 3:  2a01-260-1-1--9a.core6.t-2.net                        2.232ms 
 4:  2a01-260-1-1--39.core6.t-2.net                        3.044ms asymm  3 
 5:  hurricane-electric.nikhef.nlsix.net                  35.427ms asymm  4 
 6:  no reply
 7:  be10.core1.zrh2.he.net                               45.338ms asymm  8 
 8:  be1.core1.mil2.he.net                                34.332ms asymm  7 
 9:  no reply
10:  no reply
11:  irideos-AS3302-v6.mix-it.net                         32.874ms asymm  7 
12:  2a02:7d8:0:f::ae                                     31.383ms asymm  8 
13:  2a02:7d8:0:f::ae                                     32.515ms asymm  8 
14:  2001:1450::1                                         34.976ms reached
     Resume: pmtu 1500 hops 14 back 8