You will note there is some debate about whether the pubs in Temple Bar (a small district south of the Liffey) are "authentic." Undoubtedly, these places cater to tourists, but that includes Irish tourists, so they aren't too far off the mark. The advantage is, there are many pubs crowded into a small area, so it's easy to do a pub-crawl. And the area is safe at night, which isn't true everywhere in Dublin (I'm told).