Update README.md

README.md

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 # net_proxy
+
+## why
 a friend was in need of a proxy, for pop3 and smtp. so this is a network proxy for smtp, generic tcp but no http. input is plain, output tls. enjoy.
+
+## why no http?
+because http proxies exist on mass. in fact if you look for "smtp reverse proxy" dozens of http proxies show up and no single smtp one.
+
+## what does it do?
+for every "route" defined in the config file, it creates a little server that listens for incomming connections and creates a sort of forwarding worker connection. the incomming traffic is supposed to be unencrypted while the outgoing traffic will be tls encrypted.
+tcp is a generic type which works for most kinds of protocols while smtp is a bit more advanced specifically for smtp connections.
+
+## why no incomming tls?
+there's really only 3 reasons for you to run this tool:
+
+- you have some ancient software incapable of handling proper, modern secure tls. just let this tool handle it then tbh, as a proxy on the same machine
+- you run this as a proxy, on the same machine for other reasons
+- you somehow came up with an even more questionable use for this software
+
+## how to setup
+in the config file (config.json),
+- smtp-data-limit is the amount of bytes a single smtp message may contain.
+- smtp-timeout is the smtp timeout in seconds.
+- smtp-max-recipients is the maximum allowed amount of recipients of an email forwarded.
+I think it's pretty obvious.
+routes is an array of routes (roaring applause from the audience reading this)
+where each route defines a server listening to "port-in", and forwards the traffic to "destination" at "port-out", using either type "smtp" or "tcp".
+again, incomming traffic is plain, outgoing traffic is tls encrypted.
+
+this is highly questionable MacGuffin I wrote as a fun little go exercise a while ago and decided to put up here. so if you *need* it, that means you're running insecure or outdated (and therefore insecure) software but if you feel like switching to something else would be a huge hussle, feel free to use this software provided as is :) and have fun