WCF vs ASHX for file transfer

I need my web server to make a call through the firewall to开发者_高级运维 an internal server and retrieve a binary file. On the internal server, which is better to use: a WCF service or an ASHX file to take the request and return the bytes of the file?

If a WCF service, are there any tutorials you can direct me to as I have not done much with WCF?