AS212467 - MANDELBIT Mandelbit SRLPIRFC 4890 ✓RPKI ✓ 1/1ASPA -

AS overview

Test target: 2001:67c:2fbc::1 · static prefix probe · address space: PI · prefixes announced: 1

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

MIX-IT / NAMEX / MINAP / TOP-IX / VSIX / EQUINIX-MILAN / BGPX-ROME / NAMEX-BARI / PCIX / DECIX-PALERMO peering

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

We probed 15 arbitrary IPv6 address(es) inside AS212467's announced prefix(es). No router inside the prefix responded. The deepest visible hop was 2a0e:8f01:1000:24::1cb at hop 24 - that router does not answer ICMPv6 Echo. This is not in AS212467's announced prefix; operationally it's the AS-edge / peering interface (often on an IXP 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

Vantage points disagree about Type 2 acceptance - transit ASes on one path may be filtering Type 2 even though the destination's stack accepts it on another path:

• NL host (go6lab): Type 2 NOT honored. Forged PTB had no effect (filtered en route or stack ignored it). (ICMPv6 Echo + forged PTB)
• ITA host (Karsolink): inconclusive: no Echo Reply to 1300-byte probe. (ICMPv6 Echo + forged PTB)
• SLO host (6connect): Type 2 honored. Forged PTB accepted; next response shrunk. (ICMPv6 Echo + forged PTB)

Why they disagree - path-asymmetric Type 2 filtering: Both vantages used the ICMPv6 Echo + forged-PTB method on the same destination IP, but reached different verdicts. The destination's stack is the same in both cases - so the difference is in the path: a transit AS on one route filters our forged Type 2 (or its return ICMPv6 carrying the embedded packet) while the other route delivers it intact. The vantage that says honored shows what the destination's stack actually does; the one that says not honored shows that the path between us and them drops Type 2.

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)'

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

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

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)'

From NL host (go6lab)   echo onlyRFC 4890 ✗

filter likely at: unknown · min PMTU on path: 1462

Path (traceroute + mtr + PTR)

tracepath -6

 1?: [LOCALHOST]                        0.036ms pmtu 1462
 1:  2a00:8642:42::3                                       1.784ms 
 1:  2a00:8642:42::3                                       1.909ms 
 2:  gw.friends.steffann.nl                                2.675ms 
 3:  2a00:1ca8:1::194                                      2.738ms 
 4:  2a03:3f40::10:41                                      2.936ms 
 5:  speed-ix.pathconnect.de                              11.895ms asymm  3 
 6:  ???                                                  12.004ms asymm  4 
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     Too many hops: pmtu 1462
     Resume: pmtu 1462 

From ITA host (Karsolink)   open

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

Path (traceroute + mtr + PTR)

tracepath -6

 1?: [LOCALHOST]                        0.030ms pmtu 1500
 1:  no reply
 2:  2a12:d8c0:109f:121::a1                                1.005ms 
 3:  2a12:d8c0:101f:103::1                                 8.965ms 
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     Too many hops: pmtu 1500
     Resume: pmtu 1500 

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]                        0.032ms pmtu 1500
 1:  fw1-lju.6connect.com                                  0.631ms 
 1:  fw1-lju.6connect.com                                  0.513ms 
 2:  ccr-to-fw-ccr1-gw-lju.6connect.com                    0.717ms 
 3:  2a00:ee1:800:9::1                                     2.628ms 
 4:  2a00:ee0:1:15::2                                      1.134ms asymm  3 
 5:  2a11:4142:2002::                                      1.028ms asymm  6 
 6:  2620:107:4008:e85::2                                  8.135ms asymm  7 
 7:  navigabene-v6.mix-it.net                             17.613ms asymm 13 
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     Too many hops: pmtu 1500
     Resume: pmtu 1500