50% packet loss after cable modem upgrade???


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  • itxnc
    itxnc Posts: 87
    First Comment Friend Collector Fifth Anniversary
     Ally Member

    So… this was new (tried to SSH into the router with Putty)

    CLI via browser worked fine, but this was unexpected… We're on the 2023 WK06 firmware

  • Zyxel_Cooldia
    Zyxel_Cooldia Posts: 1,174
    Zyxel Certified Network Administrator - Security Zyxel Certified Sales Associate 50 Answers 1000 Comments
     Zyxel Employee

    Hi @itxnc,

    The most common reason for the 'Couldn't agree a key exchange algorithm' error message in PuTTY is an outdated version of the software.
    To resolve the issue, you can try upgrading to the latest version of PuTTY, which should support the latest key exchange algorithms and security protocols.
    By the way, has the issue been solved by MSO?

  • itxnc
    itxnc Posts: 87
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     Ally Member
    edited March 30

    Just to give everyone an update - best we can tell this was/is some weird issue on the ISP backend? They supposedly had techs check out the backend equipment when they "saw metrics that concerned them", but never heard one way or another. The problem seemed to dissipate. However, it does still happen, just now it's intermittent. We'll see a brief packet loss. It seems to happen more (based on ping plot) when we're on the phone. So we're seeing maybe 5-10 brief interruptions per day instead of the constant on/off packet loss that made the connection unusable until we bounced the WAN connection. Packet loss is ALWAYS at the immediate cable modem gateway (not the modem itself). But even 5-10 times a day is not great when clients are constantly saying 'I can't hear you' and sure enough a red bar pops up on PingPlotter then we get voice path back (VoIP/RingCentral). Of course, getting the ISP to agree it's their issue instead of any other vendor we use (Zyxel, RingCentral, etc) is a steep climb. But that's where we are. Best guess is when they swapped out our modem with a newer model/brand, we hit a different gateway and this problem happens.

  • mMontana
    mMontana Posts: 1,207
    50 Answers 1000 Comments Friend Collector Third Anniversary
     Guru Member


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