AS43351 GORENJE-SI-AS - Gorenje, d.o.o.

AS overview

Test target: 2001:67c:2dd8::2 · via IPv6 Hitlist (responsive) · address space: PI · prefixes announced: 1

prefix(es): 2001:67c:2dd8::/48

Targets & per-vantage-point probe results (3 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 / hostname	Source	SRB host (SOX, Belgrade)					DE host (Berlin)					DE host (Düsseldorf)					NL host (go6lab)					ITA host (Karsolink)					SLO host (6connect)					SLO host (T-2)
Target IP / hostname	Source	ping	1500B	:80	:443	reached	ping	1500B	:80	:443	reached	ping	1500B	:80	:443	reached	ping	1500B	:80	:443	reached	ping	1500B	:80	:443	reached	ping	1500B	:80	:443	reached	ping	1500B	:80	:443	reached
`2001:67c:2dd8::1`	prb	✓	✓	refused	?	✓	✓	✓	refused	?	✓	✓	✓	refused	?	✓	✓	✓	?	?	✓	✓	✓	refused	?	✓	✓	✓	refused	?	✓	✓	✓	refused	?	✓
`2001:67c:2dd8::2`	hit	✓	✓	refused	?	✓	✓	✓	refused	?	✓	✓	✓	refused	?	✓	✓	✓	?	?	✓	✓	✓	refused	?	✓	✓	✓	refused	?	✓	✓	✓	refused	?	✓
`2001:67c:2dd8::3`	hit	✓	✓	?	?	-	✓	✓	?	?	-	✓	✓	?	?	-	✓	✓	?	?	-	✓	✓	?	?	-	✓	✓	?	?	-	✓	✓	?	?	-

SIX peering

Not an SIX member, but our traceroute path crosses the SIX LAN from SLO host (T-2) - reached via an SIX-resident transit operator.

RPKI & ASPA

1 of 1 prefix(es) covered by a valid ROA.

Prefix	RPKI state	Reason	Covering VRP(s)
`2001:67c:2dd8::/48`	✓ valid	matched VRP (correct origin, length within maxLength)	AS43351 /48 maxLen 48 (ripe)

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

We probed 35 arbitrary IPv6 address(es) inside AS43351's announced prefix(es). No router inside the prefix responded. The deepest visible hop was 2a00:ee1:4500:1::2 at hop 16 - that router answers ICMPv6 Echo. This is not in AS43351'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

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 2026-09-23T10:33:06Z

Failure detail - what to grep in your logs

vantage	our source	your target	method	result	tested (UTC)
belgrade	`2a09:ab81::91`	`2001:67c:2dd8::2`	`icmp6-echo`	not_honored	2026-09-23T10:33:06Z
berlin	`2a06:d1c1:10b::cccc`	`2001:67c:2dd8::2`	`icmp6-echo`	not_honored	2026-09-23T10:33:04Z
duseldorf	`2a06:d1c1:10d::aaaa`	`2001:67c:2dd8::2`	`icmp6-echo`	not_honored	2026-09-23T10:33:03Z
go6lab	`2a00:8642:42::75`	`2001:67c:2dd8::2`	`icmp6-echo`	not_honored	2026-09-23T10:33:22Z
karsolink	`2a12:d8c0:105a:9001::a154`	`2001:67c:2dd8::2`	`icmp6-echo`	not_honored	2026-09-23T10:33:07Z
odin	`2607:fae0:a000::42`	`2001:67c:2dd8::2`	`icmp6-echo`	not_honored	2026-09-23T10:33:05Z
t2	`2a01:261:313:b814:2a0:98ff:fe5b:13e4`	`2001:67c:2dd8::2`	`icmp6-echo`	not_honored	2026-09-23T10:33:06Z

Attempt log (belgrade):

icmp6-echo → not_honored (reply shrank 1460→1460 B)
dns-tcp → no_tcp: connect failed: [Errno 111] Connection refused
tls → no_tcp: TLS connect failed
http → no_tcp: tcp/80 not open

Attempt log (berlin):

icmp6-echo → not_honored (reply shrank 1460→1460 B)
dns-tcp → no_tcp: connect failed: [Errno 111] Connection refused
tls → no_tcp: TLS connect failed
http → no_tcp: tcp/80 not open

Attempt log (duseldorf):

icmp6-echo → not_honored (reply shrank 1460→1460 B)
dns-tcp → no_tcp: connect failed: [Errno 111] Connection refused
tls → no_tcp: TLS connect failed
http → no_tcp: tcp/80 not open

Attempt log (go6lab):

icmp6-echo → not_honored (reply shrank 1460→1460 B)
dns-tcp → no_tcp: connect failed: timed out
tls → no_tcp: TLS connect failed
http → no_tcp: tcp/80 not open

Attempt log (karsolink):

icmp6-echo → not_honored (reply shrank 1460→1460 B)
dns-tcp → no_tcp: connect failed: [Errno 111] Connection refused
tls → no_tcp: TLS connect failed
http → no_tcp: tcp/80 not open

Attempt log (odin):

icmp6-echo → not_honored (reply shrank 1460→1460 B)
dns-tcp → no_tcp: connect failed: [Errno 111] Connection refused
tls → no_tcp: TLS connect failed
http → no_tcp: tcp/80 not open

Attempt log (t2):

icmp6-echo → not_honored (reply shrank 1460→1460 B)
dns-tcp → no_tcp: connect failed: [Errno 111] Connection refused
tls → no_tcp: TLS connect failed
http → no_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

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.
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.
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 (2026-09-23T10:33:06Z) 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 ↗

● 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

4/4

Echo small (56B) 28.8ms

4/4

Echo 1500B (DF) 29.0ms

yes

Type 1 dest-unreach

TCP responds on

Path (traceroute + mtr + PTR)

#	IP / PTR	RTT	mtr loss	AS	AS holder
1	2a09:ab81::1	0.2ms	0%*	AS60733	PERKE-NET - ZORAN PEROVIC trading as Agencija Perke.NET, RS
2	2001:7f8:1e::4	0.5ms	0%	AS13004	SOX - Serbian Open Exchange DOO, RS
3	ts6-vix-mb.telekom.si 2001:7f8:30:0:2:1:0:5603	27.7ms	0%	-	NA
4	2a00:ee1:4500:1::2	28.2ms	0%	AS5603	SIOL-NET - Telekom Slovenije, d.d., SI
5	2001:67c:2dd8::2	29.3ms	0%	AS43351	GORENJE-SI-AS - Gorenje, d.o.o., SI

tracepath -6

 1?: [LOCALHOST]                        0.010ms pmtu 1500
 1:  _gateway                                              0.699ms 
 1:  _gateway                                              0.563ms 
 2:  2001:7f8:1e::4                                        0.918ms 
 3:  ts6-vix-mb.telekom.si                                28.082ms asymm  6 
 4:  2a00:ee1:4500:1::2                                   28.729ms asymm  7 
 5:  2001:67c:2dd8::2                                     30.205ms reached
     Resume: pmtu 1500 hops 5 back 8

From DE host (Berlin) openRFC 4890 ✗

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

4/4

Echo small (56B) 33.2ms

4/4

Echo 1500B (DF) 33.3ms

yes

Type 1 dest-unreach

TCP responds on

Path (traceroute + mtr + PTR)

#	IP / PTR	RTT	mtr loss	AS	AS holder
1	*	-	0%*	-
2	ae0-2453.cr10.ber01.lwlcom.net 2a06:d1c0::dead:beef:1c02	0.5ms	0%*	AS59645	WYBT-NET - Tobias Fiebig, DE
3	ae0-10.cr10.ber03.lwlcom.net 2a00:c380:b200:230::220	0.8ms	0%	AS50629	LWLCOM - LWLcom GmbH, DE
4	ae0-15.cr11.dtm01.lwlcom.net 2a00:c380:b200:230::5	8.4ms	0%	AS50629	LWLCOM - LWLcom GmbH, DE
5	ae0-10.cr10.dtm02.lwlcom.net 2a00:c380:b200:230::255	8.4ms	0%	AS50629	LWLCOM - LWLcom GmbH, DE
6	ae0-50.cr10.dus02.lwlcom.net 2a00:c380:b200:230::24	8.4ms	0%	AS50629	LWLCOM - LWLcom GmbH, DE
7	ae0-10.cr10.dus01.lwlcom.net 2a00:c380:b200:230::187	8.3ms	0%	AS50629	LWLCOM - LWLcom GmbH, DE
8	ae6-60.cr10.ams01.lwlcom.net 2a00:c380:b200:230::213	11.1ms	0%	AS50629	LWLCOM - LWLcom GmbH, DE
9	as5405.frys-ix.net 2001:7f8:10f::151d:9	11.2ms	0%	-	NA
10	r7-ams1-nl.as5405.net 2a11:4140::55	32.1ms	0%	AS5405	INTERDOTLINK - Inter.link GmbH, DE
11	r7-fra1-de.as5405.net 2a11:4140::4c	32.2ms	0%	AS5405	INTERDOTLINK - Inter.link GmbH, DE
12	r5-fra1-de.as5405.net 2a11:4140::42	32.1ms	0%	AS5405	INTERDOTLINK - Inter.link GmbH, DE
13	r2-vie1-at.as5405.net 2a11:4140::1e	32.2ms	0%	AS5405	INTERDOTLINK - Inter.link GmbH, DE
14	r1-lju1-si.as5405.net 2a11:4140::38	32.0ms	0%	AS5405	INTERDOTLINK - Inter.link GmbH, DE
15	2a11:4142:2002::1	29.4ms	0%	AS5405	INTERDOTLINK - Inter.link GmbH, DE
16	2a00:ee1:4500:1::2	66.0ms	0%	AS5603	SIOL-NET - Telekom Slovenije, d.d., SI
17	2001:67c:2dd8::2	33.9ms	0%	AS43351	GORENJE-SI-AS - Gorenje, d.o.o., SI

tracepath -6

 1?: [LOCALHOST]                        0.019ms pmtu 1500
 1:  xe-0-0-13-178.gw01.ber01.as59645.net                  0.466ms 
 1:  xe-0-0-13-178.gw01.ber01.as59645.net                  0.463ms 
 2:  ae0-2453.cr10.ber01.lwlcom.net                        0.861ms 
 3:  ae0-10.cr10.ber03.lwlcom.net                          0.964ms 
 4:  ae0-15.cr11.dtm01.lwlcom.net                          9.973ms asymm  5 
 5:  ae0-10.cr10.dtm02.lwlcom.net                          8.802ms asymm  6 
 6:  ae0-50.cr10.dus02.lwlcom.net                          8.972ms asymm  3 
 7:  ae0-10.cr10.dus01.lwlcom.net                          8.754ms asymm  4 
 8:  ae6-60.cr10.ams01.lwlcom.net                         11.434ms asymm  5 
 9:  as5405.frys-ix.net                                   11.613ms 
10:  r7-ams1-nl.as5405.net                                32.495ms asymm 13 
11:  r7-fra1-de.as5405.net                                32.464ms asymm 12 
12:  r5-fra1-de.as5405.net                                32.547ms asymm 11 
13:  r2-vie1-at.as5405.net                                32.562ms asymm 10 
14:  r1-lju1-si.as5405.net                                32.260ms asymm  9 
15:  2a11:4142:2002::1                                    29.807ms asymm  7 
16:  2a00:ee1:4500:1::2                                   34.128ms asymm  9 
17:  2001:67c:2dd8::2                                     34.568ms reached
     Resume: pmtu 1500 hops 17 back 10

From DE host (Düsseldorf) openRFC 4890 ✗

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

4/4

Echo small (56B) 21.2ms

4/4

Echo 1500B (DF) 21.4ms

yes

Type 1 dest-unreach

TCP responds on

Path (traceroute + mtr + PTR)

#	IP / PTR	RTT	mtr loss	AS	AS holder
1	xe-0-0-12-142.gw01.dus01.as59645.net 2a06:d1c1:100:d::1	0.1ms	0%*	AS59645	WYBT-NET - Tobias Fiebig, DE
2	2001:7f8:9e::151d:0:1	0.4ms	0%	-	NA
3	r4-fra2-de.as5405.net 2a11:4140::b	19.6ms	0%	AS5405	INTERDOTLINK - Inter.link GmbH, DE
4	r7-fra1-de.as5405.net 2a11:4140::4c	19.6ms	0%	AS5405	INTERDOTLINK - Inter.link GmbH, DE
5	r5-fra1-de.as5405.net 2a11:4140::42	19.5ms	0%	AS5405	INTERDOTLINK - Inter.link GmbH, DE
6	r2-vie1-at.as5405.net 2a11:4140::1e	19.6ms	0%	AS5405	INTERDOTLINK - Inter.link GmbH, DE
7	r1-lju1-si.as5405.net 2a11:4140::38	19.6ms	0%	AS5405	INTERDOTLINK - Inter.link GmbH, DE
8	2a11:4142:2002::1	16.9ms	0%	AS5405	INTERDOTLINK - Inter.link GmbH, DE
9	2a00:ee1:4500:1::2	20.9ms	0%	AS5603	SIOL-NET - Telekom Slovenije, d.d., SI
10	2001:67c:2dd8::2	21.4ms	0%	AS43351	GORENJE-SI-AS - Gorenje, d.o.o., SI

tracepath -6

 1?: [LOCALHOST]                        0.024ms pmtu 1500
 1:  xe-0-0-12-142.gw01.dus01.as59645.net                  0.668ms 
 1:  xe-0-0-12-142.gw01.dus01.as59645.net                  1.014ms 
 2:  2001:7f8:9e::151d:0:1                                 0.741ms asymm  3 
 3:  r4-fra2-de.as5405.net                                19.702ms asymm 12 
 4:  r7-fra1-de.as5405.net                                19.674ms asymm 11 
 5:  r5-fra1-de.as5405.net                                19.646ms asymm 10 
 6:  r2-vie1-at.as5405.net                                19.779ms asymm  9 
 7:  r1-lju1-si.as5405.net                                19.625ms asymm  8 
 8:  2a11:4142:2002::1                                    17.014ms asymm  6 
 9:  2a00:ee1:4500:1::2                                   21.621ms asymm  8 
10:  2001:67c:2dd8::2                                     22.106ms reached
     Resume: pmtu 1500 hops 10 back 9

From NL host (go6lab) openRFC 4890 ✗

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

4/4

Echo small (56B) 123.4ms

4/4

Echo 1500B (DF) 34.4ms

yes

Type 1 dest-unreach

TCP responds on

Path (traceroute + mtr + PTR)

#	IP / PTR	RTT	mtr loss	AS	AS holder
1	2a00:8642:42::2	1.3ms	0%	AS203993	GNA-DC1-AS - S.J.M. Steffann, NL
2	*	-	-	-
3	2a00:1ca8:1::194	5.0ms	0%	AS50673	Serverius-as - Serverius Holding B.V., NL
4	2a03:3f40::10:41	2.9ms	0%	AS50673	Serverius-as - Serverius Holding B.V., NL
5	speed-ix.inter.link 2001:7f8:b7::a500:5405:1	5.4ms	0%	-	NA
6	r5-ams1-nl.as5405.net 2a11:4140::41	29.9ms	0%	AS5405	INTERDOTLINK - Inter.link GmbH, DE
7	r7-ams1-nl.as5405.net 2a11:4140::55	30.9ms	0%	AS5405	INTERDOTLINK - Inter.link GmbH, DE
8	r7-fra1-de.as5405.net 2a11:4140::4c	30.9ms	0%	AS5405	INTERDOTLINK - Inter.link GmbH, DE
9	r5-fra1-de.as5405.net 2a11:4140::42	30.7ms	0%	AS5405	INTERDOTLINK - Inter.link GmbH, DE
10	r2-vie1-at.as5405.net 2a11:4140::1e	29.6ms	0%	AS5405	INTERDOTLINK - Inter.link GmbH, DE
11	r1-lju1-si.as5405.net 2a11:4140::38	33.7ms	0%	AS5405	INTERDOTLINK - Inter.link GmbH, DE
12	2a11:4142:2002::1	30.1ms	0%	AS5405	INTERDOTLINK - Inter.link GmbH, DE
13	2a00:ee1:4500:1::2	36.1ms	0%	AS5603	SIOL-NET - Telekom Slovenije, d.d., SI
14	2001:67c:2dd8::2	35.5ms	0%	AS43351	GORENJE-SI-AS - Gorenje, d.o.o., SI

tracepath -6

 1?: [LOCALHOST]                        0.039ms pmtu 1500
 1:  ???                                                 720.055ms 
 1:  ???                                                   8.854ms 
 2:  no reply
 3:  2a00:1ca8:1::194                                      6.162ms 
 4:  2a03:3f40::10:41                                      2.899ms 
 5:  speed-ix.inter.link                                   5.322ms asymm  4 
 6:  r5-ams1-nl.as5405.net                                30.586ms asymm 15 
 7:  r7-ams1-nl.as5405.net                                31.214ms asymm 14 
 8:  r7-fra1-de.as5405.net                                30.450ms asymm 13 
 9:  r5-fra1-de.as5405.net                                31.228ms asymm 12 
10:  r2-vie1-at.as5405.net                                31.801ms asymm 11 
11:  r1-lju1-si.as5405.net                                30.983ms asymm 10 
12:  2a11:4142:2002::1                                    31.057ms asymm 10 
13:  2a00:ee1:4500:1::2                                   34.577ms asymm 12 
14:  2001:67c:2dd8::2                                     35.697ms reached
     Resume: pmtu 1500 hops 14 back 13

From ITA host (Karsolink) openRFC 4890 ✗

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

4/4

Echo small (56B) 25.1ms

4/4

Echo 1500B (DF) 25.4ms

yes

Type 1 dest-unreach

TCP responds on

Path (traceroute + mtr + PTR)

#	IP / PTR	RTT	mtr loss	AS	AS holder
1	*	-	-	-
2	*	-	0%*	-
3	*	-	90%	-
4	interlink-AS5405.mix-it.net 2001:7f8:b:100:1d1:a5d0:5405:221	8.4ms	0%	-	NA
5	r1-lju1-si.as5405.net 2a11:4140::38	15.5ms	0%	AS5405	INTERDOTLINK - Inter.link GmbH, DE
6	2a11:4142:2002::1	20.5ms	0%	AS5405	INTERDOTLINK - Inter.link GmbH, DE
7	2a00:ee1:4500:1::2	24.3ms	0%	AS5603	SIOL-NET - Telekom Slovenije, d.d., SI
8	2001:67c:2dd8::2	24.6ms	0%	AS43351	GORENJE-SI-AS - Gorenje, d.o.o., SI

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

tracepath -6

 1?: [LOCALHOST]                        0.029ms pmtu 1500
 1:  no reply
 2:  no reply
 3:  2a12:d8c0:101f:103::1                                 8.839ms 
 4:  interlink-as5405.mix-it.net                           9.770ms asymm  5 
 5:  r1-lju1-si.as5405.net                                15.992ms asymm  6 
 6:  2a11:4142:2002::1                                    20.857ms 
 7:  2a00:ee1:4500:1::2                                   25.015ms asymm  8 
 8:  2001:67c:2dd8::2                                     25.017ms reached
     Resume: pmtu 1500 hops 8 back 9

From SLO host (6connect) openRFC 4890 ✗

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

4/4

Echo small (56B) 4.7ms

4/4

Echo 1500B (DF) 5.0ms

yes

Type 1 dest-unreach

TCP responds on

Path (traceroute + mtr + PTR)

#	IP / PTR	RTT	mtr loss	AS	AS holder
1	fw1-lju.6connect.com 2607:fae0:a000::2	0.4ms	0%*	AS8038	6CONNECT - 6connect, Inc., US
2	*	-	-	-
3	2a00:ee1:800:9::1	1.9ms	0%	AS5603	SIOL-NET - Telekom Slovenije, d.d., SI
4	2a00:ee1:4500:1::2	5.0ms	0%	AS5603	SIOL-NET - Telekom Slovenije, d.d., SI
5	2001:67c:2dd8::2	6.1ms	0%	AS43351	GORENJE-SI-AS - Gorenje, d.o.o., SI

tracepath -6

 1?: [LOCALHOST]                        0.020ms pmtu 9000
 1:  fw1-lju.6connect.com                                  0.902ms 
 1:  fw1-lju.6connect.com                                  0.676ms 
 2:  ccr-to-fw-ccr1-gw-lju.6connect.com                    1.043ms 
 3:  2a00:ee1:800:9::1                                     2.477ms 
 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
22:  no reply
23:  no reply
     Too many hops: pmtu 9000
     Resume: pmtu 9000

From SLO host (T-2) openRFC 4890 ✗

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

4/4

Echo small (56B) 4.4ms

4/4

Echo 1500B (DF) 4.5ms

yes

Type 1 dest-unreach

TCP responds on

Path (traceroute + mtr + PTR)

#	IP / PTR	RTT	mtr loss	AS	AS holder
1	*	-	-	-
2	2a01:260:1::225	6.8ms	0%*	AS34779	T-2-AS - T-2, d.o.o., SI
3	2a01-260-1-1--9c.core6.t-2.net 2a01:260:1:1::9c	7.0ms	0%*	AS34779	T-2-AS - T-2, d.o.o., SI
4	2001:7f8:46::5603 @SIX	9.3ms	0%	AS51988	ARNES-SIX - ARNES, SI
5	2a00:ee1:4500:1::2	10.2ms	0%	AS5603	SIOL-NET - Telekom Slovenije, d.d., SI
6	2001:67c:2dd8::2	10.6ms	0%	AS43351	GORENJE-SI-AS - Gorenje, d.o.o., SI

tracepath -6

 1?: [LOCALHOST]                        0.025ms pmtu 1500
 1:  2a01:261:313:b814::1                                  0.981ms 
 2:  2a01:260:1::225                                       3.528ms 
 3:  2a01-260-1-1--9a.core6.t-2.net                        2.035ms 
 4:  2001:7f8:46::5603                                     5.117ms 
 5:  2a00:ee1:4500:1::2                                    5.882ms asymm  7 
 6:  2001:67c:2dd8::2                                      6.322ms reached
     Resume: pmtu 1500 hops 6 back 6