Scrummy,
I made an access to the ADSL-modem from WAN and from LAN (using access rights).
I’ll just show my config.
ADSL-modem is in bridge mode.
modem’s Web-port was changed from 80 to 9080
mikrotik’s ethernet port connected to modem has a name “eth2”, and ip 172.16.18.22/30
modem’s ip = 172.16.18.21/30
mikrotik LAN subnet = 192.168.200.0/24
allow access for external ip addresses = 175.15.x.x and 183.13.x.x
wan interface=pppoe-out
/ip address
add address=172.16.18.22/30 comment="For access to ADSL-modem" interface=eth2 network=172.16.18.20
/ip firewall address-list
add address=192.168.200.1-192.168.200.254 comment="Access to ADSL-modem" list=access-adsl
add address=175.15.x.x list=access-adsl
add address=183.13.x.x list=access-adsl
/ip firewall filter
add chain=forward comment="Allow access to ADSL-modem from Lan and Internet" dst-address=172.16.18.21 dst-port=9080 protocol=tcp src-address-list=access-adsl
/ip firewall nat
add action=dst-nat chain=dstnat comment="NAT access to ADSL-modem from Internet" dst-port=9080 in-interface=pppoe-out protocol=tcp src-address-list=access-adsl to-addresses=172.16.18.21
add action=src-nat chain=srcnat comment="NAT access to ADSL-modem from LAN" dst-port=9080 protocol=tcp src-address-list=access-adsl to-addresses=172.16.18.22
Then you need to reboot ADSL-modem.