filter housing

I am changing my oil and noticed these ridges(?) at the top and bottom of the oil filter housing. Just not sure they are suppose to be there. I purchased the car about six months ago and did an oil service and did notice the ridges at that time but was, as usual, in too big a hurry to worry...

Hey everyone, So i'm trying to change my oil by myself for the first time. However, the oil filter is just impossible to get off. I bought one of the specialty tools and still no luck. Tried a strap wrench, my hands, everything I can think of. I'm suspecting that the dealer tightened it too...

ok so i found my little leak...well big leak ...ok so i looked at my bently man...and i found a view of the oil filter housing My engine doesnt have the connection for that tube coming down on the top middle and thats where my engine is leaking oil, would there be a stock plug??? and can i get...