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Known issues and workarounds

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gdwnldsKSC edited this page Jul 10, 2026 · 2 revisions

Lost packets over ethernet standard MTU:

On linux, kernel side LRO/GRO can assemble packets and pass them to ES40 larger than the

Per issue #139 - [DEC21143]: ES40 drops incoming network packets over 1514 bytes linux systems can result in packets larger than expected for the network card, as DEC 21142/21143 cards don't support jumbo frames or anything over 1500 ethernet standard MTU.

The cause is linux kernel-side LRO/GRO functionality.

To resolve, relevant commands are:

"ethtool -K eth0 gro off" or for NetworkManager "nmcli con mod eth0 ethtool.feature-gro off", with other variants of feature-gro for nmcli being available for configuration as well depending on hardware support.

Until ES40 is advanced to re-fragment packets coming in when using pcap interfaces, this will resolve the issue. When TAP support is implemented, this will not be an issue.

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