HTTP Details


Proprietary Bi-Directional HTTP interfaces allow for secure transfer of messages between two HL7Connect systems across a public network. Like TCP/IP interfaces, both incoming and outgoing interfaces can be either a client or a server. Message transfer is accomplished using standard HTTP requests.

The principle advantages of using HTTP include:

Where possible, the sending system should be the client, however the choice of client and server is usually dictated by network topology.

Connection Name

The Connection name identifies the interface, and must be identical for both client and server using only alphanumeric characters. Use of a connection name allows multiple logical connections to run independently from the same network addresses.

Server

Field    Description
Port   
  • The port which the interface will listen on
  • The valid range of port numbers is 1 - 65535
  • Avoid ports that are used by other processes
  • Check the services file (c:\winnt\system32\drivers\etc\services or c:\windows\services) to see a list of commonly pre-assigned ports
  • On Windows XP/Server and higher, the command netstat -a will list the TCP ports that are already taken by listening processes
  • You can share a port with other HTTP Transport layers
Client Restriction    This can be used as a security measure, to restrict the IP address of the clients able to connect to HL7Connect.

NOTE: Leaving these fields blank results in open access to any client.

The IP address of the client is compared to the specified IP address. It the portions of the IP Address in the address range specified by the Mask match, then the client will be granted access. For example, if the IP Address is 10.0.0.0 and the IP Mask is 255.0.0.0 then any computers in the Class A (private) 10.x.x.x address will be able to connect to the interface

NOTE: If a reverse proxy or Network Address Translator (NAT) Device is used, the client address will be the address of the reverse proxy or NAT Device, and may not be very useful.

Time outs(Outgoing only)    If the interface is an outgoing server it has to wait for the remote client to poll the interface for a message, then it has to wait again for the remote client to return a response message. These wait periods can be configured, with the default being 120 seconds and 60 seconds respectively.

Client

Field Description
Server The network name or Internet Protocol (IP) address, and the port of the server to connect to. The name must be resolvable by DNS.
Proxy The network name or IP address, and the port of the HTTP proxy to use. The name must be resolvable by DNS.
  Username
  Password
  Domain
The proxy may require authentication from HL7Connect before accepting the request. This allows the entry of the proxy information as required. If the proxy is MS-Proxy, requiring NTLM authentication, enter the domain name as well.
Timeout How many seconds the interface waits for a response from the server
Poll Interval
(Incoming Only)
Frequency (in seconds) that the server is polled for a message
Heartbeat Frequency
(Outgoing Only)
Frequency (in seconds) that the server will be sent a "heartbeat", registering that the connection is still viable. This is tracked on both HL7Connects as "Last OK" time on the interface status page. A heartbeat is not required for an incoming interface as the Poll also functions as a heartbeat
Bridge If neither HL7Connect can act as an HTTP Server, visible to the other, a relay server "bridge" will need to be provided. See HL7Connect Bridge Service for more information


© Kestral Computing P/L 2000-2015. HL7Connect v2.00-063 generated on 30-Nov 2015
Keywords: HTTP Settings, HTTP Interfaces / Configuring