docker encounter firewall error Problem Solution

-- 报错信息
[root@localhost docker]# docker run -d -p 5000:5000 training/webapp python app.py
cc61442060cb810633a06bd6ea692a3df6b0bfcadc6a7dadfe53bf875f1ac3b9
docker: Error response from daemon: driver failed programming external connectivity on endpoint pensive_hodgkin (ae7e41e1b2b98b6b482316085c22303d8a61c02d09eb21c241132da1ea34d58a): (iptables failed: iptables --wait -t nat -A DOCKER -p tcp -d 0/0 --dport 5000 -j DNAT --to-destination 172.17.0.3:5000 ! -i docker0: iptables: No chain/target/match by that name.
(exit status 1)).

Solution:
1.kill out docker all processes
pkill docker

2. Clear all chains of nat table
iptables -t nat -F

3. Stop docker default bridge docker0
ifconfig docker0 Down

4. Remove docker0 bridge
brctl delbr docker0

5. Restart docker service
systemctl restart docker

Restart the docker container
[root @ localhost docker] # docker run -d -p 5000: 5000 training / webapp python app.py

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