[VIPlumber]

Galvanized pipe is going to corrode and close up, it's just a matter of time. Replace it all, or in sections, as you can.

As for fixing the current leak, tape + dope will to do the trick. Brass nipple is preferable over galv as stated above.

 

[junkcollector]

I personally prefer pipe dope (rectorseal) over teflon tape but have used both in the past.

Kind of odd the leak would just start all of a sudden?

 

[Jupe Blue]

Probably not odd that it started. It's a sloooow drip in a connection to my dishwasher. Located in sink cabinet. Lots of items being moved in and out, particularly the trash can. Probably got bumped one too many times.

Fixed now.