Transfer Family AS2 IP address

When you create a server using AWS Transfer Family with internet-facing connectivity, AWS provides a static IP address for that server. This IP address is for your partners to establish connections to your server. However, this doesn't mean the same IP address will be used for outbound connections from your server to your partners.

If your partner is seeing different IP addresses for incoming traffic from your server, it's likely because the outbound traffic is originating from the Elastic IP (EIP) of your NAT gateway or your VPC's Internet Gateway (depending on your configuration), not the static IP address assigned to your AS2 server.

If your partner's firewall rules are IP address-based, you might need to provide them with the IP addresses of your NAT gateways or the CIDR blocks of your VPC.

Also, ensure you have configured the necessary outbound rules in your Security Groups and NACLs, and the AS2 server is allowed to initiate connections to your partner's servers.

For more detailed troubleshooting, consider reaching out to AWS Support. They should be able to provide more specific guidance based on your configuration.