So from couple of weeks I noticed strange behavior which on the beginning I started to think that's the problem with my ISP. I called them couple of times. And they said that nothing occurs wrong on their side.

I have two devices connected : ISP Router - http://routerboard.com/RB750Gr2" / MikroTik Router RB750Gr2 hEX version 6.28 Firmware v3.23 << that's my NEW Router

Symptoms.

Ether1 stops working properly. (WAN)
Properly : ether1 is up, Tx are coming out but Rx is 0. On the first hand It seems like something is wrong with connection from my ISP.
Starting pinging IP (e.g 8.8.8.8 ) and I have timeout.
Starting pinging my network gateway and I have response.
Called my ISP he said that he can access his device and he see's my device too.

I figure it out something is wrong between My and ISP device connection. Checked cable, changed it too. Nothing. Reeboting both devices gave me nothing. Funny is that that happens sometimes only.

First of all I thought this has something to do with the new router. http://routerboard.com/RB750GL / My OLDER was MikroTik Router RB750GL and I tested on that router my connection when those strange behaviors appears. I plug the old Router and everything was working .. fine :/

I reset the mac addresses on the New router because I upload it the backup from the older mikrotik and the MAC addresses where from the old one. The problem was gone for a long while. Long I mean before I made that operation the problems occurs 3 times in week randomly. Now today I had the same problem after whole week. So now it took much more longer time to appears. But It still happens.

I don't know but something is wrong with that router. My ISP upload software again to his device and advice me to reboot his device after 15 minutes and mine to after that time. I did it and now everything is working fine. But don't now for how long. Have someone any ideas? Should I upgrade the router (hEX) from 6.28 to 6.33 ?

If someone could help with this because it's realy an issue. Starting to be more often than usual

I mean no one?

I mean no one?

I was doing my export from all important sections , steb-by-step to import to my second , older, mikrotik (RB750GL) and during that process I looked to IP/ARP. And delete just in case the APR entry of my ISP gateway, because it was with D flag (dynamic) I figure it out that after removing it , it will add itself. And it did.. and sudden ping to 8.8.8.8 start working..

Strange but I think RB750Gr2 has problem with ARP table. I decided to make a static entry of that rule. See what will happen in next few days. But for now I can say that's was the problem.

Update:

Still have problem with the Network on Ethernet (ether1 WAN). For sure it's the arp entry problem. I Made a Static ARP for my ISP gateway. It was working over 24h and sudden yesterday in 1 AM it stopped working. I had to delete the entry in ARP table , and it added automatically by it self. After that it Started working again. Very strange thing but can RB750Gv2 had some problems with ARP on WAN ?