AS51185 - MAINSTREAMING-AS MainStreaming SpARFC 4890 ✓RPKI ✓ 21/21ASPA -

AS overview

Test target: 2a02:2890:efff::1 · static prefix probe · address space: unknown · prefixes announced: 21

prefix(es): 2a02:2891:157::/48, 2a02:2891:9::/48, 2a02:2891:160::/48, 2a02:2890:efff::/48, 2a02:2891:10::/48, 2a02:2891:4::/48, 2a02:2891:16::/48, 2a02:2891:18::/48 (+13 more)

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 30 arbitrary IPv6 address(es) inside AS51185's announced prefix(es). No router inside the prefix responded. The deepest visible hop was 2001:2034:a:235::1 at hop 10 - that router answers ICMPv6 Echo. This is not in AS51185'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)   openRFC 4890 ✗

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

Path (traceroute + mtr + PTR)

tracepath -6

 1?: [LOCALHOST]                        0.026ms pmtu 1500
 1:  2a00:8642:42::3                                       1.438ms 
 1:  2a00:8642:42::3                                       1.121ms 
 2:  no reply
 3:  ccr2-ccr1.dc1.nogalliance.org                         2.792ms asymm  2 
 4:  2001:7f8:1::a505:1185:1                               6.046ms asymm  5 
 5:  no reply
 6:  no reply
 7:  no reply
 8:  no reply
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24:  no reply
     Too many hops: pmtu 1500
     Resume: pmtu 1500 

From ITA host (Karsolink)   open

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]                        0.029ms pmtu 1500
 1:  karsolink-01.net.karsolink.com                        0.748ms 
 1:  karsolink-01.net.karsolink.com                        0.862ms 
 2:  2a12:d8c0:109f:121::a1                                0.887ms 
 3:  2a12:d8c0:101f:6::1                                  10.492ms 
 4:  onecomglobal.minap.it                                11.290ms 
 5:  mainstreaming-as51185.mix-it.net                      9.866ms asymm  4 
 6:  mainstreaming-as51185.mix-it.net                     10.416ms asymm  4 
 7:  2a02:2890:0:100:0:7:0:142                            10.845ms asymm  5 
 8:  no reply
 9:  no reply
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24:  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

Path (traceroute + mtr + PTR)

tracepath -6

 1?: [LOCALHOST]                        0.038ms pmtu 1500
 1:  fw1-lju.6connect.com                                  0.673ms 
 1:  fw1-lju.6connect.com                                  0.570ms 
 2:  no reply
 3:  2a00:ee1:800:9::1                                     2.190ms 
 4:  2a00:ee0:1:10::2                                      1.266ms asymm  3 
 5:  as51185.frankfurt.megaport.com                       14.619ms asymm  8 
 6:  mainstreaming-AS51185.mix-it.net                     14.691ms 
 7:  2a02:2890:0:100:0:7:0:36                             14.941ms asymm  8 
 8:  no reply
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     Too many hops: pmtu 1500
     Resume: pmtu 1500