api.nuget.org V3 unreachable from Cosmote/OTE (Greece) — packets dropped inside Microsoft network after GR-IX peering

[giannik]

NuGet Product Used

dotnet.exe

Product Version

dotnet

Worked before?

No response

Impact

None

Repro Steps & Context

Description

The NuGet V3 API endpoint (https://api.nuget.org/v3/index.json) is completely unreachable from a Cosmote (OTE) residential connection in Greece. The legacy V2 endpoint (https://www.nuget.org/api/v2) works fine from the same connection. The V3 endpoint also works fine from a mobile data connection (different ISP).

Symptoms

• dotnet restore fails with timeout when using V3 feed
• https://api.nuget.org/v3/index.json — times out
• https://www.nuget.org/api/v2 — works fine
• Same V3 URL works from a mobile hotspot (different ISP)
• Both IPv4 and IPv6 are affected

DNS Resolution (correct)

api.nuget.org resolves to:

• IPv4: 13.107.226.72, 13.107.253.72
• IPv6: 2620:1ec:48:1::72, 2620:1ec:29:1::72

Ping (100% packet loss)

Pinging part-0044.t-0009.fb-t-msedge.net [13.107.226.72] with 32 bytes of data:
Request timed out.
Request timed out.

Traceroute to 13.107.226.72

  1    <1 ms    <1 ms    <1 ms  192.168.1.1
  2     3 ms     1 ms     1 ms  80.106.125.100
  3     2 ms     1 ms     1 ms  ampe-asr99b-ampe-asr9kb.backbone.otenet.net [79.128.242.53]
  4     8 ms     7 ms     7 ms  79.128.226.136
  5     9 ms     7 ms     7 ms  79.128.226.17
  6     9 ms     7 ms     7 ms  microsoft.gr-ix.gr [176.126.38.18]
  7    36 ms    35 ms    41 ms  ae21-0.rwa01.vie.ntwk.msn.net [104.44.40.85]
  8     *        *        *     Request timed out.
  9    46 ms    68 ms    75 ms  51.10.33.69
 10     *        *        *     Request timed out.
 ...
 30     *        *        *     Request timed out.

Traffic enters Microsoft's network at GR-IX (Greek Internet Exchange, hop 6), reaches Vienna (hop 7, ae21-0.rwa01.vie.ntwk.msn.net), then packets are dropped and never reach the destination.

Environment

• OS: Windows
• ISP: Cosmote / OTE (Greece)
• Peering point: GR-IX (microsoft.gr-ix.gr / 176.126.38.18)
• .NET SDK: (run dotnet --version and fill in)
• Date: March 22, 2026

Expected Behavior

api.nuget.org should be reachable from all major ISPs.

Verbose Logs

[pranathibora14]

Thanks for the detailed report and traceroute, @giannik! We're looking into this and we'll follow up here once we have more information.