AS21013 - ITANDTEL-AS eww agPI/PARFC 4890 ✗RPKI ✓ 3/3ASPA -

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AS overview

Test target: 2a02:940:0:4557::1002 · dns3.itandtel.at · address space: mixed · prefixes announced: 3

prefix(es): 2a06:fb80::/29, 2a02:940::/32, 2001:67c:c98::/48

Targets & per-vantage-point probe results (5 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
2a02:940:0:4292::100
ns1.itandtel.at
drv??????????????
2a02:940:0:4293::100
ns2.itandtel.at
drv??????????????
2a02:940:0:4557::1002
dns3.itandtel.at
NS??-??-??-??-??-??-??-
2a06:fb80:0:ffff::11
ns3.quattrosec.cloud
NS??????????????-
2a06:fb80::11
ns4.quattrosec.cloud
NS??????????????

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

VIX / AAIX / SAIX / TIROL-IX / ERA-IX member - Open peering, peering member, since 2010-07-29. IPv6 LAN: 2001:7f8:30:0:2:1:2:1013. Locations: -.

RPKI & ASPA

3 of 3 prefix(es) covered by a valid ROA.

PrefixRPKI stateReasonCovering VRP(s)
2a06:fb80::/29✓ validmatched VRP (correct origin, length within maxLength)AS21013 /29 maxLen 29 (ripe)
2a02:940::/32✓ validmatched VRP (correct origin, length within maxLength)AS21013 /32 maxLen 32 (ripe)
2001:67c:c98::/48✓ validmatched VRP (correct origin, length within maxLength)AS21013 /48 maxLen 48 (ripe)

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

At least one router inside AS21013's announced prefix replied during the random-target probe. Hop(s): 2a02:940::1000:0:0:10, 2a02:940::1000:0:0:8, 2a02:940::1:a. 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 2026-09-23T13:34:47Z

Failure detail - what to grep in your logs
vantageour sourceyour targetmethodresulttested (UTC)
belgrade2a09:ab81::912a02:940:0:4557::1002icmp6-echonot_honored2026-09-23T13:34:47Z
berlin2a06:d1c1:10b::cccc2a02:940:0:4557::1002icmp6-echonot_honored2026-09-23T13:34:47Z
duseldorf2a06:d1c1:10d::aaaa2a02:940:0:4557::1002icmp6-echonot_honored2026-09-23T13:34:48Z
go6lab2a00:8642:42::752a02:940:0:4557::1002icmp6-echonot_honored2026-09-23T13:35:22Z
karsolink2a12:d8c0:105a:9001::a1542a02:940:0:4557::1002icmp6-echonot_honored2026-09-23T13:34:42Z
odin2607:fae0:a000::422a02:940:0:4557::1002icmp6-echonot_honored2026-09-23T13:34:50Z
t22a01:261:313:b814:2a0:98ff:fe5b:13e42a02:940:0:4557::1002icmp6-echonot_honored2026-09-23T13:34:46Z

Attempt log (belgrade):

  1. icmp6-echonot_honored (reply shrank 1460→1460 B)
  2. dns-tcpinconclusive (reply 156 B before PTB): max DNS-over-TCP segment 156B; not big enough to test PMTU shrink
  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-tcpinconclusive (reply 156 B before PTB): max DNS-over-TCP segment 156B; not big enough to test PMTU shrink
  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-tcpinconclusive (reply 156 B before PTB): max DNS-over-TCP segment 156B; not big enough to test PMTU shrink
  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-tcpinconclusive (reply 133 B before PTB): max DNS-over-TCP segment 133B; not big enough to test PMTU shrink
  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-tcpinconclusive (reply 156 B before PTB): max DNS-over-TCP segment 156B; not big enough to test PMTU shrink
  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-tcpinconclusive (reply 156 B before PTB): max DNS-over-TCP segment 156B; not big enough to test PMTU shrink
  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-tcpinconclusive (reply 175 B before PTB): max DNS-over-TCP segment 175B; not big enough to test PMTU shrink
  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 (2026-09-23T13:34:47Z) 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 AS21013

From SRB host (SOX, Belgrade)   openRFC 4890 ✗

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

4/4
Echo small (56B) 15.1ms
4/4
Echo 1500B (DF) 15.2ms
no
Type 1 dest-unreach
-
TCP responds on

Path (traceroute + mtr + PTR)

#IP / PTRRTTmtr lossASAS holder
12a09:ab81::10.2ms0%*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
32001:7f8:1e:8::3d0.3ms0%AS13004SOX - Serbian Open Exchange DOO, RS
42a02:2d8:0:a00e:232a12.7ms10%-
52001:7f8:30:0:2:1:2:1013 @VIX / AAIX / SAIX / TIROL-IX / ERA-IX14.6ms50%-NA
6*-60%-
72a02:940::1000:0:0:1015.2ms0%AS21013ITANDTEL-AS - eww ag, AT
82a02:940:0:4851::215.5ms0%AS21013ITANDTEL-AS - eww ag, AT
9*-0%-
10*---
11*---
12*---
13*---
14*---
15*---
16*---
17*---
18*---
19*---
20*---
21*---

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

tracepath -6

 1?: [LOCALHOST]                        0.010ms pmtu 1500
 1:  _gateway                                              0.593ms 
 1:  _gateway                                              0.402ms 
 2:  sox-pn.sox.rs                                         0.666ms 
 3:  2001:7f8:1e:8::3d                                     0.658ms asymm  2 
 4:  ae8-930.RT.IRX.VIE.AT.retn.net                       13.152ms asymm  3 
 5:  no reply
 6:  no reply
 7:  2a02:940::1000:0:0:10                                15.527ms asymm  5 
 8:  2a02:940:0:4851::2                                   17.342ms 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 DE host (Berlin)   openRFC 4890 ✗

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

4/4
Echo small (56B) 25.9ms
4/4
Echo 1500B (DF) 25.9ms
no
Type 1 dest-unreach
-
TCP responds on

Path (traceroute + mtr + PTR)

#IP / PTRRTTmtr lossASAS holder
1*-0%*-
2ae0-2453.cr10.ber01.lwlcom.net
2a06:d1c0::dead:beef:1c02
0.7ms0%*AS59645WYBT-NET - Tobias Fiebig, DE
3ae3-90.cr10.ham01.lwlcom.net
2a00:c380:b200:230::192
4.7ms0%AS50629LWLCOM - LWLcom GmbH, DE
4ae0-50.cr11.ham01.lwlcom.net
2a00:c380:b200:230::45
5.0ms0%AS50629LWLCOM - LWLcom GmbH, DE
52a00:c380:f000::4b5.3ms0%AS50629LWLCOM - LWLcom GmbH, DE
6ae4-2087.dus10.core-backbone.com
2a01:4a0:0:2087::33
11.2ms0%AS201011CORE-BACKBONE - Core-Backbone GmbH, DE
7ae43-2026.fra30.core-backbone.com
2a01:4a0:0:2026::1
11.0ms0%AS201011CORE-BACKBONE - Core-Backbone GmbH, DE
8ae16-2123.fra40.core-backbone.com
2a01:4a0:0:2123::42
11.2ms0%AS201011CORE-BACKBONE - Core-Backbone GmbH, DE
9ae8-2027.muc10.core-backbone.com
2a01:4a0:0:2027::6
15.3ms0%AS201011CORE-BACKBONE - Core-Backbone GmbH, DE
10ae1-2030.muc20.core-backbone.com
2a01:4a0:0:2030::7
15.3ms0%AS201011CORE-BACKBONE - Core-Backbone GmbH, DE
11ae1-2028.vie10.core-backbone.com
2a01:4a0:0:2028::10
20.7ms0%AS201011CORE-BACKBONE - Core-Backbone GmbH, DE
12*-70%-
13*---
142a02:940::1000:0:0:1025.5ms0%AS21013ITANDTEL-AS - eww ag, AT
152a02:940:0:4851::226.5ms0%AS21013ITANDTEL-AS - eww ag, AT
16*-0%-
17*---
18*---
19*---
20*---
21*---

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

tracepath -6

 1?: [LOCALHOST]                        0.022ms pmtu 1500
 1:  xe-0-0-13-178.gw01.ber01.as59645.net                  1.267ms 
 1:  xe-0-0-13-178.gw01.ber01.as59645.net                  0.332ms 
 2:  ae0-2453.cr10.ber01.lwlcom.net                        0.783ms 
 3:  ae3-90.cr10.ham01.lwlcom.net                          5.035ms 
 4:  ae0-50.cr11.ham01.lwlcom.net                          5.278ms 
 5:  2a00:c380:f000::4b                                    5.562ms asymm  4 
 6:  ae4-2087.dus10.core-backbone.com                     11.463ms asymm  5 
 7:  ae43-2026.fra30.core-backbone.com                    11.400ms asymm  5 
 8:  ae16-2123.fra40.core-backbone.com                    11.627ms asymm  6 
 9:  ae8-2027.muc10.core-backbone.com                     15.340ms asymm  8 
10:  ae1-2030.muc20.core-backbone.com                     15.443ms asymm  7 
11:  ae1-2028.vie10.core-backbone.com                     20.887ms asymm  8 
12:  no reply
13:  no reply
14:  2a02:940::1000:0:0:10                                26.071ms asymm  7 
15:  2a02:940:0:4851::2                                   26.201ms asymm  8 
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

4/4
Echo small (56B) 21.3ms
4/4
Echo 1500B (DF) 21.4ms
no
Type 1 dest-unreach
-
TCP responds on

Path (traceroute + mtr + PTR)

#IP / PTRRTTmtr lossASAS holder
1*-0%*-
2eth1-0-12-h5594.edge5-dus1.bb.wiit.network
2001:4ba0:92f4:3::1
9.0ms0%AS24961MYLOC-AS - WIIT AG, DE
3*---
4lag30.core3-dus1.bb.wiit.network
2001:4ba0:ffe9:109::2
0.2ms0%AS24961MYLOC-AS - WIIT AG, DE
5lag2.core1-dus-ix.bb.wiit.network
2001:4ba0:ffe9:4f::1
0.4ms0%AS24961MYLOC-AS - WIIT AG, DE
6*---
7*---
82a02:940::1000:0:0:1021.1ms0%AS21013ITANDTEL-AS - eww ag, AT
92a02:940:0:4851::222.0ms0%AS21013ITANDTEL-AS - eww ag, AT
10*-0%-
11*---
12*---
13*---
14*---
15*---
16*---
17*---
18*---
19*---
20*---
21*---

tracepath -6

 1?: [LOCALHOST]                        0.047ms pmtu 1500
 1:  xe-0-0-12-142.gw01.dus01.as59645.net                  0.323ms 
 1:  xe-0-0-12-142.gw01.dus01.as59645.net                  0.193ms 
 2:  eth1-0-12-h5594.edge5-dus1.bb.wiit.network            5.350ms 
 3:  no reply
 4:  lag11.core3-dus1.bb.wiit.network                      0.402ms 
 5:  lag2.core1-dus-ix.bb.wiit.network                     0.516ms 
 6:  fra.corou0010.v6.as21013.net                         21.444ms asymm  7 
 7:  no reply
 8:  2a02:940::1000:0:0:10                                21.647ms 
 9:  2a02:940:0:4851::2                                   22.355ms 
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

4/4
Echo small (56B) 23.4ms
4/4
Echo 1500B (DF) 95.5ms
no
Type 1 dest-unreach
-
TCP responds on

Path (traceroute + mtr + PTR)

#IP / PTRRTTmtr lossASAS holder
12a00:8642:42::21.7ms0%AS203993GNA-DC1-AS - S.J.M. Steffann, NL
2gw.friends.steffann.nl
2a00:8642:1000:f000::1
3.9ms0%*AS203993GNA-DC1-AS - S.J.M. Steffann, NL
3*---
4*-90%-
5*---
62a02:940::1000:0:0:1023.1ms0%AS21013ITANDTEL-AS - eww ag, AT
72a02:940:0:4851::224.3ms0%AS21013ITANDTEL-AS - eww ag, AT
8*-0%-
9*---
10*---
11*---
12*---
13*---
14*---
15*---
16*---
17*---
18*---
19*---
20*---
21*---

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

tracepath -6

 1?: [LOCALHOST]                        0.039ms pmtu 1500
 1:  2a00:8642:42::2                                       3.634ms 
 1:  2a00:8642:42::2                                       3.692ms 
 2:  gw.friends.steffann.nl                                2.511ms 
 3:  no reply
 4:  no reply
 5:  no reply
 6:  2a02:940::1000:0:0:10                                24.392ms asymm  9 
 7:  2a02:940:0:4851::2                                   26.256ms asymm 10 
 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 ITA host (Karsolink)   openRFC 4890 ✗

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

4/4
Echo small (56B) 22.5ms
3/4
Echo 1500B (DF) 22.7ms
no
Type 1 dest-unreach
-
TCP responds on

Path (traceroute + mtr + PTR)

#IP / PTRRTTmtr lossASAS holder
1*---
2*---
3*---
4*-0%-
5be47.core1.mil2.he.net
2001:470:e:69::2
11.7ms10%AS6939HURRICANE - Hurricane Electric LLC, US
6be1.core1.zrh2.he.net
2001:470:e:dd::2
15.1ms20%AS6939HURRICANE - Hurricane Electric LLC, US
7be10.core4.fra1.he.net
2001:470:e:153::1
20.6ms0%AS6939HURRICANE - Hurricane Electric LLC, US
8*---
9*-0%-
10*-0%-
112a02:940::1000:0:0:1021.5ms0%AS21013ITANDTEL-AS - eww ag, AT
122a02:940:0:4851::221.8ms-AS21013ITANDTEL-AS - eww ag, AT
13*---
14*---
15*---
16*---
17*---
18*---
19*---
20*---
21*---

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

tracepath -6

 1?: [LOCALHOST]                        0.010ms pmtu 1500
 1:  no reply
 2:  no reply
 3:  no reply
 4:  zayo-AS6461.mix-it.net                                8.914ms 
 5:  ae9.cr2.fra9.de.zip.zayo.com                         26.532ms asymm  6 
 6:  be1.core1.zrh2.he.net                                15.780ms 
 7:  ae8.er1.mun1.de.zip.zayo.com                         26.116ms asymm  5 
 8:  no reply
 9:  no reply
10:  2a02:940::1:a                                        22.441ms asymm  7 
11:  2a02:940::1000:0:0:10                                22.375ms asymm  8 
12:  2a02:940:0:4851::2                                   22.904ms asymm  9 
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: 1500

4/4
Echo small (56B) 16.5ms
4/4
Echo 1500B (DF) 16.5ms
no
Type 1 dest-unreach
-
TCP responds on

Path (traceroute + mtr + PTR)

#IP / PTRRTTmtr lossASAS holder
1fw1-lju.6connect.com
2607:fae0:a000::2
0.4ms0%*AS80386CONNECT - 6connect, Inc., US
2*---
32a00:ee1:800:9::11.6ms40%AS5603SIOL-NET - Telekom Slovenije, d.d., SI
42a00:ee0:1:10::21.3ms0%AS5603SIOL-NET - Telekom Slovenije, d.d., SI
5*-0%-
6*-20%-
72a02:940::1000:0:0:1016.6ms0%AS21013ITANDTEL-AS - eww ag, AT
82a02:940:0:4851::217.4ms0%AS21013ITANDTEL-AS - eww ag, AT
9*-0%-
10*---
11*---
12*---
13*---
14*---
15*---
16*---
17*---
18*---
19*---
20*---
21*---

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

tracepath -6

 1?: [LOCALHOST]                        0.024ms pmtu 9000
 1:  fw1-lju.6connect.com                                  0.851ms 
 1:  fw1-lju.6connect.com                                  0.654ms 
 2:  no reply
 3:  2a00:ee1:800:9::1                                     2.481ms 
 4:  2a00:ee0:1:15::2                                      1.394ms asymm  3 
 5:  2a00:ee0:1:10::2                                      7.329ms pmtu 1500
 5:  fra.corou0010.v6.as21013.net                         16.764ms 
 6:  2a02:940::1:a                                        16.864ms asymm  5 
 7:  2a02:940::1000:0:0:10                                17.289ms asymm  6 
 8:  2a02:940:0:4851::2                                   17.208ms asymm  7 
 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

From SLO host (T-2)   openRFC 4890 ✗

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

4/4
Echo small (56B) 13.1ms
4/4
Echo 1500B (DF) 13.4ms
no
Type 1 dest-unreach
-
TCP responds on

Path (traceroute + mtr + PTR)

#IP / PTRRTTmtr lossASAS holder
1*---
22a01:260:1::2258.1ms0%*AS34779T-2-AS - T-2, d.o.o., SI
32a01-260-1-1--9c.core6.t-2.net
2a01:260:1:1::9c
4.0ms0%*AS34779T-2-AS - T-2, d.o.o., SI
42a01-260-1-1--38.core6.t-2.net
2a01:260:1:1::38
3.9ms-AS34779T-2-AS - T-2, d.o.o., SI
5100ge0-0-0-31.core1.vie1.he.net
2001:470:0:4a8::1
13.1ms0%AS6939HURRICANE - Hurricane Electric LLC, US
6100ge0-0-0-31.core1.vie1.he.net
2001:470:0:4a8::1
13.3ms90%AS6939HURRICANE - Hurricane Electric LLC, US
7*---
8*-0%-
92a02:940::1000:0:0:1015.9ms0%AS21013ITANDTEL-AS - eww ag, AT
10*-0%-
11*---
12*---
13*---
14*---
15*---
16*---
17*---
18*---
19*---
20*---
21*---

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

tracepath -6

 1?: [LOCALHOST]                        0.026ms pmtu 1500
 1:  2a01:261:313:b814::1                                  0.712ms 
 2:  2a01:260:1::225                                       6.660ms 
 3:  2a01-260-1-1--9a.core6.t-2.net                        2.115ms 
 4:  2a01-260-1-1--38.core6.t-2.net                        2.289ms asymm  3 
 5:  no reply
 6:  100ge0-0-0-31.core1.vie1.he.net                      12.872ms asymm  5 
 7:  2001:7f8:30:0:2:1:2:1013                             13.460ms asymm  5 
 8:  2a02:940::1000:0:0:10                                13.029ms asymm  7 
 9:  2a02:940:0:4851::2                                   14.425ms asymm  8 
10:  2a02:940:0:4851::2                                   14.552ms asymm  8 
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