MRTG Monitoring with ESXi Hosted Guest Return ‘interface is commented * has no ifSpeed property’

Recently at a network, I migrated the mikrotik base RB configuration to esxi base VM guest. Everything went fine, this Mikrotik have snmp configured, and it is monitored via linux base MRTG for various probes. after migration, mrtg graph for itnerfaces stopped with following (when i re run the cfgmaker)

### The following interface is commented out because:
### * has no ifSpeed property

After playing with the itnerfaces & mrtg values, I found two solutions

Solution # 1

Network adapter need to be “E1000″ rather then  “flexible”.  Then SNMP will see the ifspeed correctly.
To make changes, its recommended to turn off the guest.

Solution # 2

Assign this speed in bits-per-second to all interfaces which return 0 for ifSpeed and ifHighSpeed

Create the cfg file with following syntax “–zero-speed=100000000 ”

 cfgmaker -zero-speed=100000000 snmp_community@192.168.1.1 > mikrotik.cfg

[192.168.1.1 is mikrotik ip]