Commita985442fde("selftests: net: properly support IPv6 in GSO GRE test") is not compatible with: Ncat: Version 7.80 ( https://nmap.org/ncat ) (which is distributed with Fedora/Red Hat), tests fail with: nc: invalid option -- 'N' Let's switch to socat which is far more dependable. Fixes:025efa0a82("selftests: add simple GSO GRE test") Fixes:a985442fde("selftests: net: properly support IPv6 in GSO GRE test") Tested-by: Andrea Righi <andrea.righi@canonical.com> Link: https://lore.kernel.org/r/20211111162929.530470-1-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>