First time with mesa - no ping but blinking user led on card

Hello everyone, i m a brand new user of Linux cnc (mach3 user - i quitted due to too much bugs and wrong reliability of the software)
i ordered a mesa 7i96s card and installed linuxcnc on a computer. 
i m quite disapointed because the first step of setting a connection doesn't work.
i set the manuel ipv4 ip adress to 10.10.10.11 (or 1 or 100) and ping 10.10.10.10 always give me no connection to the board. I tried to play with jumper position, without success (down down / down up for eeprom). Strange thing : the user led on mesa board are blinking in a additive pattern when sending packets, then stop moving when cancel ping on pc, so the communication exist ?
Is there a firmware issue of some sort ? The card is new from eusurplus.
Sorry if my question is silly.

Hello Tommylight, thank for your time and help !
After a good night, the ping 10.10.10.10 finally works (idk why), i managed to setup the pncconf wizard and open linuxcnc, but still a connexion issue i guess because i get several warnings at startup :
"Unexpected realtime delay on task 0 with period 1000000."
hm2/hm2_7i96s.0: error finishing read! iter=1598"
Moreover, my homing switch does light up the mesa board and flicker when i use them, but they appear as fixed in Halshow (show on but no flickering). I suppose the connexion break at startup of linuxcnc ? I can't figure out why and it so frustrating !

Real time issues are usually network latency related.

Can you run this command?

sudo chrt 99 ping -i .001 -c 60000 -q 10.10.10.10

and post the results here

Also have you run a latency test and done all the standard things to reduce host latency?

(All power management and CPU speed switching disabled, isolcpus set to last CPU etc etc)

Also what Ethernet hardware in on the host ? (Realtek hardware often needs it driver changed to the DKMS driver
and Intel hardware should have IRQ coalescing disabled)