Methods, systems and computer program products for delivering content objects over the Internet are disclosed. Use of a packet size digest allows for look-up of known or discovered maximum packet sizes for network paths to various receiving systems by servers within one or more points of presence of a content delivery network, such that the packet size information can be advantageously re-used by the multiple servers to reduce delays associated with lost packets and time spent determining a path maximum packet size or maximum transmission unit by each of the multiple servers within the point of presence as they transmit content objects over the Internet.