Bom dia amigo, ja tive o mesmo problema e vou te explicar o que acontece: Não podemos colocar como gateway-interface uma interface ethernet (ether1, ether2). Colocar o gateway como interface, só funciona para interfaces ponto-a-ponto (ppp-client, pppoe-client, etc). No caso as interfaces ethernet sao interfaces broadcast portanto nao funciona colocando as mesmas como gateway diretamente.
No caso do Virtua, nao tem oq fazer... só um roteador na frente mesmo, no caso do GVT é só colocar o modem em bridge, criar um pppoe-client no mikrotik, e no /ip route , colocar a interface como sendo esse pppoe-client. Faça como no exemplo abaixo (ja testado em outras ocasioes e funcionando muito bem), supondo que 192.168.0.1 seja o ip do roteador que recebe o virtua, e o virtua seja a rota padrao do sistema:
# RB 450G com MK 3.28
# Link1 - netvirtua = ether1
# Link2 - GVT bridge = pppoe-out1
# Clientes - hotspot = ether4
# Substitua o user e password do pppoe-client conforme as nescessidades
/interface pppoe-client
add ac-name="" add-default-route=no allow=pap,chap,mschap1,mschap2 comment="" dial-on-demand=no disabled=no interface=\
ether2 max-mru=1480 max-mtu=1480 mrru=disabled name=pppoe-out1 password=12345678 profile=default service-name="" \
use-peer-dns=no [email protected]
/ip address
add address=192.168.0.2/24 broadcast=192.168.0.255 comment="" disabled=no interface=ether1 network=192.168.0.0
/ip dns
set allow-remote-requests=yes cache-max-ttl=1w cache-size=4096KiB \
max-udp-packet-size=512 primary-dns=189.38.95.95 secondary-dns=\
189.38.95.96
/ip firewall mangle
add action=accept chain=prerouting comment="SEM BALANCE" disabled=no \
dst-address-list=sem_balance in-interface=ether4
add action=mark-connection chain=input comment="" connection-state=new \
disabled=no in-interface=ether1 new-connection-mark=conn_na passthrough=\
yes
add action=mark-connection chain=input comment="" connection-state=new \
disabled=no in-interface=ether2 new-connection-mark=conn_nb passthrough=\
yes
add action=mark-routing chain=output comment="" connection-mark=conn_na \
disabled=no new-routing-mark=to_ra passthrough=no
add action=mark-routing chain=output comment="" connection-mark=conn_nb \
disabled=no new-routing-mark=to_rb passthrough=no
add action=mark-connection chain=prerouting comment="" disabled=no \
dst-address-type=!local in-interface=ether4 connection-state=new new-connection-mark=conn_ma0 \
passthrough=yes per-connection-classifier=both-addresses:2/0
add action=mark-connection chain=prerouting comment="" disabled=no \
dst-address-type=!local in-interface=ether4 connection-state=new new-connection-mark=conn_mb1 \
passthrough=yes per-connection-classifier=both-addresses:2/1
add action=mark-routing chain=prerouting comment="" connection-mark=conn_ma0 \
disabled=no in-interface=ether4 new-routing-mark=to_ra passthrough=no
add action=mark-routing chain=prerouting comment="" connection-mark=conn_mb1 \
disabled=no in-interface=ether4 new-routing-mark=to_rb passthrough=no
/ip firewall nat
add action=masquerade chain=srcnat out-interface=ether1 comment="NAT" disabled=no
add action=masquerade chain=srcnat out-interface=pppoe-out1 disabled=no
/ip route
add comment="" disabled=no distance=1 dst-address=0.0.0.0/0 gateway=192.168.0.1
add comment="" disabled=no distance=1 dst-address=0.0.0.0/0 gateway=192.168.0.1 \
routing-mark=to_ra
add comment="" disabled=no distance=2 dst-address=0.0.0.0/0 gateway=pppoe-out1
add comment="" disabled=no distance=1 dst-address=0.0.0.0/0 gateway=pppoe-out1 \
routing-mark=to_rb
