Raul Magana-Herrera appeals his 240-month sentence—imposed below the applicable guideline range—after pleading guilty to one count of conspiracy to distribute and possess with intent to distribute 50 grams or more of methamphetamine, in violation of 21 U.S.C. §§ 846, 841(b)(l)(A)(viii)(Count 1).

Briefly stated, Magana-Hedera argues that his sixth grade education prevented him from knowingly and voluntarily entering into the portion of the plea agreement that waived his right to appeal. If the appeal waiver is held invalid, MaganaHerrera argues that the district court incorrectly applied a firearm enhancement and a role in the offense enhancement. In addition, Magana-Herrera argues that his 240-month sentence constitutes cruel and unusual punishment, in violation of the Eighth Amendment, and that this claim is excepted from his appeal waiver. *

First, because the district court properly conducted a plea colloquy that discussed the appeal waiver before accepting Magana-Herrera’s plea, the appeal waiver was knowing, voluntary, and enforceable. Accordingly, all grounds for appeal not ex *836 cepted from the appeal waiver are waived, including Magana-Herrera’s challenges to his offense level enhancements. Second, although Magana-Herrera claims, for the first time on appeal, that he received ineffective assistance of counsel at sentencing, we decline to consider that claim. Third, Magana-Herrera’s sentence is not cruel and unusual, in violation of the Eighth Amendment, because it is within the statutory limits; and it is not grossly disproportionate to the offense he committed. For background, see United States v. Johnson, 451 F.3d 1239, 1243 (11th Cir. 2006) (Eighth amendment violation requires showing sentence imposed is grossly disproportionate to offense committed); United States v. Grinard-Henry, 399 F.3d 1294, 1296 (11th Cir. 2005) (defendant understood the full significance of appeal waiver); Williams v. United States, 396 F.3d 1340, 1342 (11th Cir. 2005) (upholding waiver of collateral challenge to ineffectiveness of counsel at sentencing); Massaro v. United States, 538 U.S. 500, 123 S.Ct. 1690, 155 L.Ed.2d 714 (2003) (ineffective assistance claims generally not considered on direct appeal).

Accordingly, we, in the light of the appeal waiver, dismiss the appeal, in part, and otherwise affirm.

DISMISSED IN PART, AFFIRMED IN PART.