dual wan- 1 adsl and 1 proxy setup help

Firstly Id like to thank everyone in advance that will be helping me with this problem.

I would like to ask for assistance with the following senario…
I have a rb750 that I would like to use to combine 2 internet connections namely WAN1 and WAN2
to work with the use of wan failover on my network

Wan1 is a internet connection that only allows surfing through a proxy server address= 10.10.10.100:3128
Wan2 is a standard adsl connection = 192.168.0.1
LanA = eth3 is setup as my guest hotspot on range 192.168.10.1/24
LanB = Eth 4&5 setup for office use on range 192.168.20.1/24

I am able with the basic configuration to get my 2 Lan networks to surf on the Wan2 internet without
issues but have no cooking clue how to configure the Wan1 internet connection and utilize failover.

Can anybody assist with something basic for a noob like myself?

And I do apologize in advance if this question has been answered before. I just cant seem to find a viable solution

Load balancing / failover isn’t a basic topic. It isn’t difficult once you understand all the parts involved.

See this presentation by Tomas Kirnak:

https://www.youtube.com/watch?v=67Dna_ffCvc
PDF: http://mum.mikrotik.com/presentations/US12/tomas.pdf

Thanks for the response,
I don’t have a problem understanding the concept of the fail over and load balancing per say, my issue is with the line that requires me to enter a proxy server before I can surf.
My normal adsl line is working fine but I have no idea how to configure the second line.
If I plug my laptop direct to this line, issue myself a static IP address and insert the proxy settings in the web browser with allocated port then I surf no problem so I know it isn’t the line.

I just need advice on where to configure the Mikrotik for the proxy settings and port.

Thanks for your help

Does the proxy need authentication? Do you want to send HTTP traffic through both DSLs, or all HTTP traffic to the proxy?

Basically what you should do is either:

1.- Do not mangle HTTP traffic, and create an specific nat rule to dst-nat outgoing HTTP traffic to the proxy (all HTTP traffic through proxy DSL line)

2.- Mangle and divide HTTP traffic specifically, then dst-nat part of them through the DSL proxy, and proceed a usual in load-balancing for the rest.

Thank you for your response.
Id like to utilize both wan ports for traffic in this solution aswell and implement the failover if one line does not work. No additional authenticating required on the proxy besides the ip address and port configuration

Would it be possible for you to assist me with the firewall commands to setup as this is where Ill probably fall off the wagon.

Many thanks

Sure, try it and post your /ip export and /interface export configuration.