以下是使用AWS SES和AWS Lambda动态创建转发到外部地址的邮箱的解决方案：

1. 在AWS SES控制台中创建一个可信的发信地址。这将是用于发送邮件的地址。
2. 在AWS Lambda控制台中创建一个新的函数。
3. 在代码编辑器中添加以下代码：

import boto3

def lambda_handler(event, context):
    # 获取要创建的邮箱地址和要转发的外部地址
    mailbox = event['mailbox']
    forwarding_address = event['forwarding_address']
    
    # 创建一个新的邮箱规则
    client = boto3.client('ses')
    response = client.create_receipt_rule(
        RuleSetName='default-rule-set',
        Rule={
            'Name': mailbox,
            'Enabled': True,
            'Recipients': [
                mailbox,
            ],
            'Actions': [
                {
                    'S3Action': {
                        'TopicArn': 'arn:aws:sns:us-east-1:123456789012:MyTopic',
                        'BucketName': 'email-bucket',
                        'ObjectKeyPrefix': 'email/',
                        'EncryptionConfiguration': {
                            'S3EncryptionAction': {
                                'KmsKeyArn': 'arn:aws:kms:us-east-1:123456789012:key/12345678-1234-5678-1234-567812345678'
                            }
                        }
                    }
                },
                {
                    'LambdaAction': {
                        'FunctionArn': 'arn:aws:lambda:us-east-1:123456789012:function:MyLambdaFunction'
                    }
                },
                {
                    'AddHeaderAction': {
                        'HeaderName': 'X-SES-MESSAGE-TAGS',
                        'HeaderValue': 'mailbox={}'.format(mailbox)
                    }
                },
                {
                    'BounceAction': {
                        'SmtpReplyCode': '550',
                        'Message': 'Mailbox does not exist'
                    }
                },
                {
                    'WorkmailAction': {
                        'OrganizationArn': 'arn:aws:workmail:us-east-1:123456789012:organization/OrganizationId',
                        'TopicArn': 'arn:aws:sns:us-east-1:123456789012:MyTopic'
                    }
                },
                {
                    'StopAction': {}
                }
            ]
        }
    )
    
    # 添加转发规则到新创建的邮箱
    response = client.create_receipt_rule_set(
        RuleSetName='default-rule-set',
        Rules=[
            {
                'Name': 'forwarding-rule',
                'Enabled': True,
                'Recipients': [
                    mailbox,
                ],
                'Actions': [
                    {
                        'S3Action': {
                            'TopicArn': 'arn:aws:sns:us-east-1:123456789012:MyTopic',
                            'BucketName': 'email-bucket',
                            'ObjectKeyPrefix': 'email/',
                            'EncryptionConfiguration': {
                                'S3EncryptionAction': {
                                    'KmsKeyArn': 'arn:aws:kms:us-east-1:123456789012:key/12345678-1234-5678-1234-567812345678'
                                }
                            }
                        }
                    },
                    {
                        'LambdaAction': {
                            'FunctionArn': 'arn:aws:lambda:us-east-1:123456789012:function:MyLambdaFunction'
                        }
                    },
                    {
                        'AddHeaderAction': {
                            'HeaderName': 'X-SES-MESSAGE-TAGS',
                            'HeaderValue': 'mailbox={}'.format(mailbox)
                        }
                    },
                    {
                        'BounceAction': {
                            'SmtpReplyCode': '550',
                            'Message': 'Mailbox does not exist'
                        }
                    },
                    {
                        'WorkmailAction': {
                            'OrganizationArn': 'arn:aws:workmail:us-east-1:123456789012:organization/OrganizationId',
                            'TopicArn': 'arn:aws:sns:us-east-1:123456789012:MyTopic'
                        }
                    },
                    {
                        'StopAction': {}
                    }
                ]
            }
        ]
    )
    
    # 创建一个转发规则，将收到的邮件转发到外部地址
    response = client.create_receipt_rule(
        RuleSetName='default-rule-set',
        Rule={
            'Name': 'forwarding-rule',
            'Enabled': True,
            'Recipients': [
                mailbox,
            ],
            'Actions': [
                {
                    'WorkmailAction': {
                        'OrganizationArn': 'arn:aws:workmail:us-east-1:123456789012:organization/O