使用时报错：

1.dnf  install tcpflow 

warning: /var/cache/dnf/epel-2b6dfc5904c26562/packages/tcpflow-1.4.5-1.el7.x86_64.rpm: Header V3 RSA/SHA256 Signature, key ID 352c64e5: NOKEY

解决方法：

dnf --nogpgcheck install tcpflow

参考：https://www.poftut.com/rpm-yum-dnf-nokey-public-key-check-error-and-solution/