2 Mikrotiks (each of them are connected with an SDSL line) are tunneled together via eoip-tunnel.
On each side is a windows server with a smb-share.
I can transfer small files (<10MB) in both directions, i can browse the shares,
print on a remote printer and so on without a problem.
But if i try to transfer larger files (>15MB), the transfer getting stalled after a few megabytes.
The tunnel is active, i can ping the remote windows server without any problems, normal latency,
and even with 1472 bytes payload (mtu 1500) no problems.
I didn’t see anything in the windows eventlog and i have tried it also with 2 other computers instead
of the servers, same behaviour.
It happens only when files are transfered via the tunnel, no problem when files are copied locally (one computer to the server in the lan).
why does this happen only with larger files? could it be a problem on the eoip-tunnel?
Make sure you are not accidentally NAT’ing the connections across/through the EoIP tunnel. If this is happening, the SMB server will see multiple SMB sessions/users from the same IP. Each time it does, it will terminate the previous session/user and create a new one. Smaller/faster operations seem to work, but on longer/slower ones, the probability of having a second SMB request come in from the same NAT’ed IP during the longer operation increases and it appears that bigger file copies fail. You can see if this is occurring by looking at the SMB server’s connection table or session/user list and see if the IP’s listed are what you expect. You shouldn’t see the IP of one of the Mikrotik’s as an IP in the SMB session table.
I have similar problem with one central location that has several eoip tunnels bridged using stp protocol. Internet, video surveillance and other service work, but when user try to copy file to some remote location, the file of valid size is created, but corrupted and user receive that network resource is not available and to check network configuration.
This started I think, when I upgraded router os from version 5x to 6.1.x.