AS56843 - CNT-ISP-AS Centar Novih Tehnologija DOOPI/PARFC 4890 ✓RPKI ✓ 1/1ASPA -

← back to summary

All countriesHomeState of IPv6TopologySOXAboutipv6.si ↗ Sparky

AS overview

Test target: 2a02:2951::1 · static prefix probe · address space: mixed · prefixes announced: 1

prefix(es): 2a02:2951::/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
2a02:2951::1prb??????????????

SOX peering

Not an SOX member, but our traceroute path crosses the SOX LAN from SRB host (SOX, Belgrade) - reached via an SOX-resident transit operator.

RPKI & ASPA

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

PrefixRPKI stateReasonCovering VRP(s)
2a02:2951::/32✓ validmatched VRP (correct origin, length within maxLength)AS56843 /32 maxLen 32 (ripe)

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

We probed 35 arbitrary IPv6 address(es) inside AS56843's announced prefix(es). No router inside the prefix responded. The deepest visible hop was 2a02:b58:1:15::2 at hop 8 - that router answers ICMPv6 Echo. This is not in AS56843's announced prefix; operationally it's the AS-edge / peering interface (often on a SOX 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 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 2026-09-23T11:08:31Z

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 AS56843

From SRB host (SOX, Belgrade)   openRFC 4890 ✓

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

4/4
Echo small (56B) 23.2ms
4/4
Echo 1500B (DF) 23.6ms
yes
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
2orion.sox.rs @SOX
2001:7f8:1e::23
19.6ms80%AS9125Orion Telekom
32a02:b58:1:15::219.6ms80%AS9125ORIONTELEKOM-AS - Drustvo za telekomunikacije Orion telekom doo Beograd-Zemun, RS
42a02:660:1:1::1223.7ms-AS9125ORIONTELEKOM-AS - Drustvo za telekomunikacije Orion telekom doo Beograd-Zemun, RS
52a02:2951::124.3ms-AS56843CNT-ISP-AS - Centar Novih Tehnologija DOO, RS

Rate-limited ICMPv6: hop 2, hop 3 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).

tracepath -6

 1?: [LOCALHOST]                        0.019ms pmtu 1500
 1:  _gateway                                              0.541ms 
 1:  _gateway                                              0.285ms 
 2:  no reply
 3:  no reply
 4:  ???                                                  23.459ms asymm 11 
 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
     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) 34.3ms
4/4
Echo 1500B (DF) 34.9ms
yes
Type 1 dest-unreach
-
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
2xe-0-0-12-2412.gw01.dus01.as59645.net
2a06:d1c0::dead:beef:401
8.4ms0%AS59645WYBT-NET - Tobias Fiebig, DE
3eth1-0-12-h5594.edge5-dus1.bb.wiit.network
2001:4ba0:92f4:3::1
10.3ms0%AS24961MYLOC-AS - WIIT AG, DE
4lag10-h5f01.agr4-dus1.bb.wiit.network
2001:4ba0:ffe9:7c::1
10.1ms0%AS24961MYLOC-AS - WIIT AG, DE
5lag30.core3-dus1.bb.wiit.network
2001:4ba0:ffe9:109::2
8.3ms0%AS24961MYLOC-AS - WIIT AG, DE
6lag8.core1-dus-ix.bb.wiit.network
2001:4ba0:ffe9:8::2
8.4ms0%AS24961MYLOC-AS - WIIT AG, DE
7*-70%-
8*-70%-
92a02:660:1:1::1233.6ms-AS9125ORIONTELEKOM-AS - Drustvo za telekomunikacije Orion telekom doo Beograd-Zemun, RS
102a02:2951::136.9ms-AS56843CNT-ISP-AS - Centar Novih Tehnologija DOO, RS

Rate-limited ICMPv6: hop 7, hop 8 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).

tracepath -6

 1?: [LOCALHOST]                        0.028ms pmtu 1500
 1:  xe-0-0-13-178.gw01.ber01.as59645.net                  0.489ms 
 1:  xe-0-0-13-178.gw01.ber01.as59645.net                  0.443ms 
 2:  xe-0-0-12-2412.gw01.dus01.as59645.net                 8.451ms 
 3:  eth1-0-12-h5594.edge5-dus1.bb.wiit.network            9.905ms 
 4:  no reply
 5:  lag30.core3-dus1.bb.wiit.network                      8.663ms 
 6:  lag8.core1-dus-ix.bb.wiit.network                     8.852ms 
 7:  2001:7f8::23a5:0:1                                   32.036ms 
 8:  ???                                                  31.188ms 
 9:  ???                                                  34.158ms 
10:  no reply
11:  no reply
12:  no reply
13:  no reply
14:  no reply
15:  no reply
16:  no reply
17:  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) 26.4ms
4/4
Echo 1500B (DF) 26.7ms
yes
Type 1 dest-unreach
-
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
4.0ms0%AS24961MYLOC-AS - WIIT AG, DE
3lag13.agr3-dus3.bb.wiit.network
2001:4ba0:ffe9:7d::1
2.2ms0%AS24961MYLOC-AS - WIIT AG, DE
4lag11.core3-dus1.bb.wiit.network
2001:4ba0:ffe9:115::3
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*-70%-
7*-70%-
82a02:660:1:1::1227.0ms-AS9125ORIONTELEKOM-AS - Drustvo za telekomunikacije Orion telekom doo Beograd-Zemun, RS
92a02:2951::126.9ms-AS56843CNT-ISP-AS - Centar Novih Tehnologija DOO, RS

Rate-limited ICMPv6: hop 6, hop 7 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).

tracepath -6

 1?: [LOCALHOST]                        0.012ms pmtu 1500
 1:  xe-0-0-12-142.gw01.dus01.as59645.net                  0.235ms 
 1:  xe-0-0-12-142.gw01.dus01.as59645.net                  0.233ms 
 2:  eth1-0-12-h5594.edge5-dus1.bb.wiit.network            1.840ms 
 3:  no reply
 4:  lag11.core3-dus1.bb.wiit.network                      0.393ms 
 5:  lag8.core1-dus-ix.bb.wiit.network                     0.477ms 
 6:  no reply
 7:  no reply
 8:  ???                                                  26.241ms 
 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
     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) 37.4ms
4/4
Echo 1500B (DF) 36.2ms
yes
Type 1 dest-unreach
-
TCP responds on

Path (traceroute + mtr + PTR)

#IP / PTRRTTmtr lossASAS holder
12a00:8642:42::21.2ms0%AS203993GNA-DC1-AS - S.J.M. Steffann, NL
2*-0%*-
32a00:1ca8:1::1943.4ms0%AS50673Serverius-as - Serverius Holding B.V., NL
42a03:3f40::10:337.6ms0%AS50673Serverius-as - Serverius Holding B.V., NL
5ae22-404.ams10.core-backbone.com
2a01:4a0:1338:155::1
6.2ms0%AS201011CORE-BACKBONE - Core-Backbone GmbH, DE
6ae16-2074.fra10.core-backbone.com
2a01:4a0:0:2074::3
14.5ms0%AS201011CORE-BACKBONE - Core-Backbone GmbH, DE
7ae2-2021.fra20.core-backbone.com
2a01:4a0:0:2021::4
14.2ms0%AS201011CORE-BACKBONE - Core-Backbone GmbH, DE
82001:7f8::23a5:0:133.6ms70%-NA
92a02:b58:1:15::233.2ms70%AS9125ORIONTELEKOM-AS - Drustvo za telekomunikacije Orion telekom doo Beograd-Zemun, RS
102a02:660:1:1::1236.6ms-AS9125ORIONTELEKOM-AS - Drustvo za telekomunikacije Orion telekom doo Beograd-Zemun, RS
112a02:2951::140.4ms-AS56843CNT-ISP-AS - Centar Novih Tehnologija DOO, RS

Rate-limited ICMPv6: hop 8, hop 9 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).

tracepath -6

 1?: [LOCALHOST]                        0.135ms pmtu 1500
 1:  2a00:8642:42::2                                       1.245ms 
 1:  2a00:8642:42::2                                       4.073ms 
 2:  gw.friends.steffann.nl                                2.444ms 
 3:  2a00:1ca8:1::194                                      3.697ms 
 4:  2a03:3f40::10:33                                     10.731ms 
 5:  ae22-404.ams10.core-backbone.com                      8.400ms 
 6:  ae16-2074.fra10.core-backbone.com                    12.044ms 
 7:  ae2-2021.fra20.core-backbone.com                     12.037ms 
 8:  no reply
 9:  no reply
10:  ???                                                  35.101ms asymm  9 
11:  no reply
12:  no reply
13:  no reply
14:  no reply
15:  no reply
16:  no reply
17:  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) 39.3ms
3/4
Echo 1500B (DF) 61.1ms
yes
Type 1 dest-unreach
-
TCP responds on

Path (traceroute + mtr + PTR)

#IP / PTRRTTmtr lossASAS holder
1*---
2*---
3*---
42a03:b020:1:51::a10.0ms0%AS41327FIBERTELECOM-AS - Fiber Telecom S.p.A., IT
52a03:b020::22418.6ms0%AS41327FIBERTELECOM-AS - Fiber Telecom S.p.A., IT
62001:7f8::23a5:0:137.6ms0%-NA
72a02:b58:1:15::235.9ms0%AS9125ORIONTELEKOM-AS - Drustvo za telekomunikacije Orion telekom doo Beograd-Zemun, RS
82a02:660:1:1::1239.2ms-AS9125ORIONTELEKOM-AS - Drustvo za telekomunikacije Orion telekom doo Beograd-Zemun, RS
92a02:2951::139.7ms-AS56843CNT-ISP-AS - Centar Novih Tehnologija DOO, RS

tracepath -6

 1?: [LOCALHOST]                        0.029ms pmtu 1500
 1:  no reply
 2:  2a12:d8c0:109f:121::a1                                0.659ms 
 3:  2a12:d8c0:101f:6::1                                   9.889ms 
 4:  2a03:b020:1:51::a                                    10.437ms 
 5:  2a03:b020::224                                       19.093ms 
 6:  2001:7f8::23a5:0:1                                   36.591ms 
 7:  ???                                                  36.593ms 
 8:  ???                                                  40.417ms 
 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
     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) 35.9ms
4/4
Echo 1500B (DF) 36.6ms
yes
Type 1 dest-unreach
-
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
2*---
32a00:ee1:800:9::11.9ms30%AS5603SIOL-NET - Telekom Slovenije, d.d., SI
42a00:ee0:1:10::21.1ms0%AS5603SIOL-NET - Telekom Slovenije, d.d., SI
5*-10%-
6*-10%-
72a02:660:1:1::1236.9ms-AS9125ORIONTELEKOM-AS - Drustvo za telekomunikacije Orion telekom doo Beograd-Zemun, RS
82a02:2951::137.1ms-AS56843CNT-ISP-AS - Centar Novih Tehnologija DOO, RS

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

tracepath -6

 1?: [LOCALHOST]                        0.026ms pmtu 9000
 1:  fw1-lju.6connect.com                                  0.559ms 
 1:  fw1-lju.6connect.com                                  0.423ms 
 2:  no reply
 3:  2a00:ee1:800:9::1                                     2.504ms 
 4:  2a00:ee0:1:15::2                                      1.317ms asymm  3 
 5:  2a00:ee0:1:15::2                                      2.382ms pmtu 1500
 5:  2001:7f8::23a5:0:1                                   32.649ms asymm  9 
 6:  ???                                                  33.070ms asymm 10 
 7:  ???                                                  37.356ms asymm 11 
 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
     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) 18.3ms
4/4
Echo 1500B (DF) 19.1ms
yes
Type 1 dest-unreach
-
TCP responds on

Path (traceroute + mtr + PTR)

#IP / PTRRTTmtr lossASAS holder
1*---
22a01:260:1::2252.3ms0%*AS34779T-2-AS - T-2, d.o.o., SI
32a01-260-1-1--9c.core6.t-2.net
2a01:260:1:1::9c
2.7ms0%*AS34779T-2-AS - T-2, d.o.o., SI
42001:7f8:28::64:05.1ms0%*-NA
52001:7f8:28::64:04.8ms0%-NA
62a02:2608:ffff:ffff:185:151:132:23110.5ms0%AS44306Omonia - OMONIA d.o.o., HR
7*-50%-
82a02:660:1:1::1219.3ms50%AS9125ORIONTELEKOM-AS - Drustvo za telekomunikacije Orion telekom doo Beograd-Zemun, RS
92a02:2951::119.8ms-AS56843CNT-ISP-AS - Centar Novih Tehnologija DOO, RS

Rate-limited ICMPv6: hop 7, hop 8 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).

tracepath -6

 1?: [LOCALHOST]                        0.028ms pmtu 1500
 1:  no reply
 2:  2a01:260:1::225                                       7.651ms 
 3:  2a01-260-1-1--9a.core6.t-2.net                        2.538ms 
 4:  2a01-260-1-1--38.core6.t-2.net                        2.331ms asymm  3 
 5:  2a02:2608:ffff:ffff:185:151:132:231                  10.526ms 
 6:  2a02:2608:ffff:ffff:185:151:132:231                  10.148ms asymm  5 
 7:  no reply
 8:  ???                                                  19.414ms 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
     Too many hops: pmtu 1500
     Resume: pmtu 1500