Anycast address for network address translation at edge

A non-transitory machine-readable medium storing a program which when executed by at least one processing unit forwards data messages at a particular edge node of a plurality of edge nodes of a logical network that process data messages between a logical network and an external network, the program comprising:

• receiving a data message sent from a source machine in the logical network;
• performing network address translation to translate a source network address of the data message corresponding to the source machine into an anycast network address that is shared among the plurality of edge nodes;
• and
• sending the data message with the anycast network address to the external network, wherein each edge node in the plurality of edge nodes receives data messages from source machines in the logical network and translates the source addresses of the data messages into the same anycast public network address prior to sending the data messages to the external network;
• wherein:
• the set of instructions for performing network address translation comprises a set of instructions for modifying a source transport layer port number of the data message;
• and
• each of the edge nodes uses a full available range of transport layer port numbers for network address translation.