Getting oil leak from the backend of engine.

First, thought my oil pan is leaking so I spend few bucks on a new gasket.

While, I was degreasing my engine bay and carriage. I spotted the little(bastard) red plug next to the oil filter is the culprit.

Apparently, this plug is leaking not the oil pan gasket.

Could someone help out, what's this Red plug called on the right and what this Left black plug called.





Better picture.

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1995 gs Saved from the crusher
1998 RS gone to(Dsm Heaven)
1997 gs gone to Dsm heaven