diff --git a/main.tf b/main.tf
index ea0070a..0f737ea 100644
--- a/main.tf
+++ b/main.tf
@@ -44,4 +44,82 @@ resource "aws_subnet" "subnet_3" {
   tags = {
     Name = "subnet-3"
   }
-}
\ No newline at end of file
+}
+
+resource "aws_subnet" "subnet_4_public" {
+  vpc_id     = aws_vpc.main.id
+  cidr_block = var.subnet_4_public_cidr
+  availability_zone = var.availability_zone_1
+  map_public_ip_on_launch = true
+
+  tags = {
+    Name = "subnet-4-public"
+  }
+}
+
+resource "aws_internet_gateway" "igw" {
+  vpc_id = aws_vpc.main.id
+
+  tags = {
+    Name = "internet-gateway"
+  }
+}
+
+resource "aws_route_table" "public_route_table" {
+  vpc_id = aws_vpc.main.id
+
+  route {
+    cidr_block = "0.0.0.0/0"
+    gateway_id = aws_internet_gateway.igw.id
+  }
+
+  tags = {
+    Name = "public-route-table"
+  }
+}
+
+resource "aws_route_table_association" "public_subnet_assoc" {
+  subnet_id      = aws_subnet.subnet_4_public.id
+  route_table_id = aws_route_table.public_route_table.id
+}
+
+resource "aws_eip" "nat" {
+  vpc = true
+}
+
+resource "aws_nat_gateway" "nat" {
+  allocation_id = aws_eip.nat.id
+  subnet_id     = aws_subnet.subnet_4_public.id
+
+  tags = {
+    Name = "nat-gateway"
+  }
+}
+
+resource "aws_route_table" "private_route_table" {
+  vpc_id = aws_vpc.main.id
+
+  route {
+    cidr_block = "0.0.0.0/0"
+    gateway_id = aws_nat_gateway.nat.id
+  }
+
+  tags = {
+    Name = "private-route-table"
+  }
+}
+
+resource "aws_route_table_association" "private_subnet_1_assoc" {
+  subnet_id      = aws_subnet.subnet_1.id
+  route_table_id = aws_route_table.private_route_table.id
+}
+
+resource "aws_route_table_association" "private_subnet_2_assoc" {
+  subnet_id      = aws_subnet.subnet_2.id
+  route_table_id = aws_route_table.private_route_table.id
+}
+
+resource "aws_route_table_association" "private_subnet_3_assoc" {
+  subnet_id      = aws_subnet.subnet_3.id
+  route_table_id = aws_route_table.private_route_table.id
+}
diff --git a/variables.tf b/variables.tf
index 5458109..8f294c4 100644
--- a/variables.tf
+++ b/variables.tf
@@ -5,19 +5,19 @@ variable "aws_region" {
 }
 
 variable "availability_zone_1" {
-  description = "Zona de disponibilidade para a primeira Subnet"
+  description = "Zona de disponibilidade 1a"
   type        = string
   default     = "us-east-1a"
 }
 
 variable "availability_zone_2" {
-  description = "Zona de disponibilidade para a segunda Subnet"
+  description = "Zona de disponibilidade 1b"
   type        = string
   default     = "us-east-1b"
 }
 
 variable "availability_zone_3" {
-  description = "Zona de disponibilidade para a terceira Subnet"
+  description = "Zona de disponibilidade 1c"
   type        = string
   default     = "us-east-1c"
 }
@@ -44,4 +44,10 @@ variable "subnet_3_cidr" {
   description = "CIDR block da terceira Subnet"
   type        = string
   default     = "10.0.3.0/24"
+}
+
+variable "subnet_4_public_cidr" {
+  description = "CIDR block da quarta Subnet (publica)"
+  type        = string
+  default     = "10.0.4.0/24"
 }
\ No newline at end of file