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Why can't connect by udp?

Received Response


i open udp port by firewalld, and test by iperf and udp server, but i can't get response, ACK.

but netcat tool says connection success.

Content (required):

[email protected]****:~$ sudo firewall-cmd --list-all


 target: default

 icmp-block-inversion: no



 services: dhcpv6 dhcpv6-client http https imap ldap mysql ssh

 ports: 3000/tcp 80/tcp 22/tcp 433/tcp 3001/tcp 3002/tcp 3006/tcp 3007/tcp 25565/tcp 3306/tcp 5900-5910/tcp 8000-8900/tcp 30037/tcp 24454/tcp 51820/udp 24450-24453/udp 24455-24460/udp 24454/udp 25565/udp


 forward: yes

 masquerade: no




 rich rules: 

[email protected]****:~$ netstat -nul

Active Internet connections (only servers)

Proto Recv-Q Send-Q Local Address      Foreign Address     State    

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