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OpenVPN "TLS cannot locate HMAC" UDP only

Discussion in 'Tomato Firmware' started by WillyTP, Jan 12, 2018.

  1. WillyTP

    WillyTP Network Newbie Member

    Hello everybody.
    I'm running Tomato since several months now, now with latest Kille72's 2017.3 version.

    Since a few days I'm experiencing a weird issue.
    With OpenVPN, 100% working configuration, all same keys / data ecc ecc (tried all from scratch too),

    when I try to connect via TCP, everything works fine

    when I try to connect via UDP, I always get the following error:
    TLS Error: cannot locate HMAC in incoming packet from [AF_INET6]

    The only thing changed in the last time is my mobile network operator
    (I connect from smartphone to my home VPN)
    Could be this? My mobile operator doing something to UDP packets?!

    Any ideas?
    Changing UDP port makes no difference.
    Only way to make UDP working is to disable "Extra HMAC authorization".

    Last edited: Jan 12, 2018
  2. pomidor1

    pomidor1 Serious Server Member

    Port Forwarding / UPnP/Nat-PMP on
    etc. UPnP on
  3. eibgrad

    eibgrad Network Guru Member

    What are we talking about here? OpenVPN client, OpenVPN server? Which side is producing the error? Your description is just too vague in this regard. Just saying "OpenVPN" isn't enough.

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