eoipv6-tunnel fragmentation problem

RouterOS General
1

Hello!

seems like eoipv6 tunnel interface is not able to fragment full size Ethernet packets for ROS version 6.38.3

I trying to build EOIP tunnel over IPV6 for ethernet lan with standart MTU 1500 without success for large packets

The largest packet may transmitted is 1416 bytes tested by ping

Any ideas? I am using two HEX routers connected each-other in test lab

No IPSEC is in use but have plans to use when fragmentation problem will be solved

I tried to use default L3 MTU size for eoipv6 1444. Also tried to change it to lower values with no luck

Site to site Layer 2 VPN with full ethernet MTU -- over IPv6
2

@mikrotik guys How I can submit a bug report?

3

Same symptom.

CCR1036-8G-2S+ (6.41.3) ⇔ EoIPv6 Tunnel ⇔ CCR1016-12S-1S+

WinPing Packet Testing ( ping IPv4Address -f -l PacketSize )
Win10(ipv4) ⇔ CCR1036 ⇔ EoIPv6 Tunnel ⇔ CCR1016 ⇔ Win10(ipv4)
No response: 1472~1379byte (MTU: 1500-1407byte)
Answer: 1378~0byte (MTU: 1406-28byte )

MTU: 1500-1407
There seems to be a range where packets are corrupted.

4

Hello,
the problem still exists and the function do-not-fragment=no seems not to be available at eoipv6
Anyone an idea?

5

I’m afraid only a workaround is currently available:

  • create an ipipv6 tunnel between the IPv6 endpoints
  • assign some IPv4 addresses to the ipipv6 interfaces as /32 ones, indicating the one assigned to the remote ipipv6 interface as the network item of each address row
  • set up an IPv4 EoIP tunnel between these auxiliary IPv4 addresses

This way, the IPv4 EoIP should do the IPv4 fragmentation, using the MTU indicated by the ipipv6 tunnel.