Smaug is aware of the return of Sauron, and was apparently intent on joining forces with him (although there was some amount of confusion as to whether the dragon's motives for an alliance with Sauron were).
Peter Jackson certainly makes the assertion in the theatrical and extended editions of the Hobbit movies that Smaug and Sauron are not only well aware of each other, but are planning to ally with each other.
The whole reason why Gandalf got the dwarves and Bilbo on their mission to Erebor was because he feared an alliance between Sauron and Smaug. While it was unlikely that the dragon would serve Sauron, a collaboration was more than possible in Gandalf's mind (and his mind tended to be spot on).
It is later revealed that Smaug's attack on Erebor was all part of Sauron's design, meaning that Smaug and Sauron were in league with each other. Smaug was considered one of the highlights of the second film of the series; several critics hailed him as cinema's greatest dragon.
This is a very interesting question, however things are quite different in the book and in the movie, the short answer is that Smaug probably didn't know about the ring nor Sauron, the long answer is explained below.
Smaug's dragon-fine would not have been hot enough to destroy the One Ring. The malevolence that Sauron put inside of the Ring could only be destroyed in the Cracks of Doom, so Frodo was compelled to make the journey to Mordor.
Smaug could easily have cut through the armies of Mordor, and delayed the invasion of Middle-earth by years. So it wasn't in Sauron's interest to take on the dragon, but that doesn't mean he saw it as a lost cause, as he fully planned on creating an alliance.
That title falls to Ancalagon the Black, the largest dragon ever to have existed in Middle-earth. He was bred by Morgoth during the First Age to fight for the Dark Lord during his campaign of terror.
Although both the Balrog and Smaug are creatures of fire, and Gandalf is able to match them thanks to the power of his fire ring, defeating the Balrog takes far more spiritual prowess, which is why Gandalf is able to essentially 'level up' and comes back as Gandalf the White, whereas defeating such an immense physical ...
Gandalf's main reason for supporting Thorin's quest in The Hobbit was to eliminate the threat of the dragon Smaug, who would be a powerful ally for Sauron. Despite popular belief, the Balrog known as Durin's Bane was more powerful than Smaug in Middle-earth, being a literal, primordial demon.
Sauron was portrayed by Benedict Cumberbatch through voice and motion capture in The Hobbit: An Unexpected Journey, The Desolation of Smaug, and the upcoming The Battle of the Five Armies. Sauron is the overarching antagonist of the trilogy, given that he made a pact with Smaug and is Azog's boss and leader.
Described as a "long-worm", although this imprecise term seems to be more of an expression rather than a separate taxonomic group. Smaug — the last great dragon of Middle-earth, slain by Bard of Esgaroth.
"She's helped to save him," Clark said. "She's also inspired him, and she'll always know that." After Galadriel makes it clear to Halbrand that she knows he is Sauron, he makes a pitch for her to join him. Halbrand says Galadriel can become his queen, and that she will bind him to light while he will bind her to power.
Despite Smaug's great size, strength and Durable hide, Sauron's Dark Magic, Powerful Weaponry and Great Intelligence ultimately triumphed over Smaug. Sauron was immune to Smaug's fire as Sauron has control over fire and had adapted to it.
Smaug. Smaug was considered to be the last "great" dragon of Middle-earth. Sauron allied with Smaug and intended to use the dragon's powers against the people of Middle-earth. But before that could happen, Smaug was slain by Bard the Bowman.
Bilbo evades him and hides behind a massive pillar, still under the cloak of the ring. Smaug continues his search and claims that he is aware of the Ring in Bilbo's possession and that he sensed that Bilbo has something "made of gold, but far more precious," which in turn forces the Hobbit to remove the Ring.
The Balrogs and Sauron were all Maiar and somewhat coeval; it is debatable whether a Balrog would recognize Sauron as successor and serve him willingly. However, if one considers the chronology of events in the Third Age then a certain "relationship" or understanding becomes evident.
Sauron never becomes bound to Middle Earth like Melkor or the Balrogs during the first age because Sauron kept shifting shape, Sauron takes more different forms than any other being in the legendarium. Thus he did not become bound to a single form like Melkor and the Balrogs.
Assuming the One Ring was destroyed, Galadriel's ring would also start to fade, causing Lothlórien to lose its glory and magic. So, when Galadriel refused the One Ring, she wasn't just sacrificing her desire to rule. She knew that she was sacrificing her kingdom and its well-being for the sake of peace in Middle-earth.
Unbeknownst to the Free Peoples, the Dragon was also in league with the Dark Lord, who had lured him to his side with promises of wealth and power. Their secret pact required Smaug to join Sauron's Orc armies at Erebor as part of a campaign to reclaim the former lands of Angmar and conquer northern Middle-earth.
Most cannot learn more once they hatch and grow, with a few exceptions. The feral dragons also have their own languages. Tolkien had at least Smaug speak human languages (in The Hobbit; I haven't read The Silmarillion to know if his other dragons spoke) and being fond of riddles, drawn from fairy tales and old lore.
