I have mikrotik Ver 4.16 operating on one pc and it works good for 1 year.
It was working from a DSL router.

My router ip for wan card was 172.30.7.208/24
My router ip was 172.30.7.225 reachable external

Now Our new ISP give us internet from cable with proxy server 192.168.11.200
And port is 8080

When I try the cable on a pc with ip 172.30.7.208 and proxy 192.168.11.200:8080
The internet is working

Now I do not know how to enter the new ISP proxy server for mikrotik input wan card ????

Please help !!!!!

If my mikrotik working settings helps I can send it here !!!!!

try this

Thanks for your help but I try and it is not working
this is my rules:

/ip firewall nat
add action=masquerade chain=srcnat comment="" disabled=no out-interface=\
!Internal
add action=redirect chain=dstnat comment="" disabled=no dst-port=80 \
in-interface=External protocol=tcp to-ports=8080
add action=redirect chain=dstnat comment="" disabled=no dst-port=80 protocol=\
tcp to-ports=8080
add action=dst-nat chain=dstnat comment="proxy access" disabled=no dst-port=\
80 protocol=tcp to-addresses=192.168.100.228 to-ports=8080

/ip route
add comment="" disabled=no distance=1 dst-address=0.0.0.0/0 gateway=\
172.30.7.254 scope=30 target-scope=10

/ip address
add address=172.30.7.208/24 broadcast=172.30.7.255 comment="" disabled=no \
interface=External network=172.30.7.0
add address=172.30.5.252/24 broadcast=172.30.5.255 comment="" disabled=no \
interface=Internal network=172.30.5.0
add address=172.30.4.252/24 broadcast=172.30.4.255 comment="" disabled=no \
interface=Mangers network=172.30.4.0

172.30.7.254 is the router which I take internet from it
192.168.100.228 is the isp proxy server
8080 is the proxy server port

So what is wrong ???

try this

No way it is not working
Any other idea