I had a similar problem with samba (on jessie), but under slightly different conditions. Under full load the interface went down and it took several minutes to retrieve connectivity.
hello and thanks for your reply :-) I've same problem also if I set low bandwidthmy server has 3 different ethernet NICs, so I can exclude a driver problems...
Btw: I wouldn't specify any "socket options" unless you're having performance problems. Under normal conditions the parameters are automatically adjusted and manually tuning these parameters might worsen you're performance (see man smb.conf).
ok thanks! Pol