[CentOS] network disconnection after several hours

Wed May 6 16:02:47 UTC 2020
Simon Matter <simon.matter at invoca.ch>

> Hello,
> 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.

Are you really sure it happens because of the firewall? Anything in the
logs indicating it happens because firewalld fiddles with something? I
gues by firewall you mean firewalld.

Usually such situations can come from NetworkManager with its default
configuration. If, for some reason, an ethernet device looses link for a
short time, NetworkManager is eager to bring down the interface and the
result is the nice "no route to host" situation. To prevent NM from
"helping" you in this situation, you have to install the server subpackage
from NM - or get rid of it :-)