[CentOS] network disconnection after several hours

Wed May 6 14:46:59 UTC 2020
Thomas Poty <thomaspoty at yahoo.fr>

Here is the context during the problem occurs : 

We have a new machine running on centos 8.From this machine, we restore a postgresql dump on an other machine runnning on centos 7.After several hoursof running, restore fails due to a disconnection (no route to host).But, if we disable the firewall on centos 8, restore succeed.
Before having this new centos 8 machine, we had a centos 7 machine and all worked fine with firewall activated.

Has anyboby an ideas, clues or something else?

Thomas Poty