Basic usage

• Run this on an independant IP
• Set a domain's lowest priority MX to be that IP
• Leave the Teergrube to it

What it will do

The teergrube's job is basically to sit on SMTP connections for as long as seems sensible. By being very slow at responding to SMTP commands and using SMTP continuation responses wherever possible will improve our ability in this respect...

SMTP commands we'll recognise, and what to do

• connect - Wait a period of time and say a 220 message back
• HELO/EHLO - Record the helo hostname if provided. reply with a 10 line result one second per line
• MAIL FROM: - Accept it. Reply with a 20 line result, one second per line, starting after 10 seconds
• RCPT TO: - Accept it. Reply with a 30 line result, one second per line, starting 15 seconds later
• DATA -- Accept it. Reply with one line after 30 seconds
• end of data -- reply with a 4xx code after 30 seconds
• RSET -- reply with one line after 20 seconds
• QUIT -- reply with a 40 line result, one second per line, after 20 seconds

Basic state for a given connection

• helo hostname provided?
• sender provided?
• in data?
• current prewait
• current wait_per_repeat
• current repeats left
• current code
• current message

Basic processing order for a connection

Every second, the following runs for active connections...

if prewait > 0 then
   prewait = prewait - 1
   return
end

if repeats > 0 then
   repeats = repeats - 1
   prewait = wait_per_repeat
   output( current_code .. "-@" .. repeats )
   return
end

if( current_code > 0 ) then
   output( current_code .. " " .. current_message )
   current_code = 0
   return
end

-- Not waiting to send stuff, so let's read a line instead

if( got_a_line ) then
   process according to the list above, setting prewait, repeats, wait_per_repeat, current_code and current_message appropriately
end