IPP - Print via HTTP or HTTPS
The Internet Printing Protocol (IPP) is a standard network protocol for remote printing as well as managing print jobs, media size, resolution, and so forth in distributed environments.
The idea behind the IPP is to define a protocol for end users to print over the Internet, provide users with the same printing controls and concepts that they use to print locally or to LAN-attached printers. There are two main components to IPP:
- Web-based printer management which offers the ability to administer, to connect to, and to view printers by using a Web browser.
- Internet printing which allows you to use the printer's URL to connect to a printer.
In IPP, print jobs are sent using Hypertext Transfer Protocol (HTTP), the same protocol used to connect to web pages. Unlike other printing protocols, IPP also supports access control, authentication, and encryption, making it a much more capable and secure printing solution than older ones.
As IPP transfers are made using HTTP v. 1.1, once a connection is made, multiple commands (files) can be sent over a single TCP connection. However, by using HTTP/1.1, IPP faces criticism for its protocol overloading. This allegedly makes for a more complex and bloated protocol and implementation than necessary — for example the venerable lp protocol was extended to cover the same functionality.
Anyway, the advantage of implementing IPP on top of HTTP is in the fact that the latter protocol is already well-tested on the Internet as a method to transfer files, which enables reuse of proven, well-tested and debugged client and server code.
It is a design goal of IPP to not invent new security features when existing protocols can be used. For example, the original RFC suggested authorization be done for example via HTTP's Digest access authentication mechanism or via SSL3. Encryption is not done by IPP itself either, but it may be handled by SSL/TLS protocol layer.
Because the service is using HTTP or HTTPS, this is typically port 80 or port 443. As IPP supports HTTPS traffic, communication can be encrypted, depending on the user’s Internet browser settings. IPP printing via HTTPS is offered in Windows XP and Windows Server 2003. Windows Vista and Windows Server 2008 also support IPP printing over RPC in Medium-Low security zone. IPP uses the client/server model, where the client resides in a PC or workstation and the server is embedded in a printer device or resides in a separate print server machine. The process is as follows:
1. Client will always initiates the communication with the server. The user connects to a print server over the Internet by typing the URL for the print device.
2. The HTTP request is sent over the network to the print server.
3. The print server requires the client to provide authentication information. This ensures that only authorized users print documents on the print server.
4. Once the user is authenticated, the server presents status information to the user by using Active Server Pages (ASP), which contain information about currently available printers.
5. When the user connects to any of the printers on the Internet printing Web page, the client first tries to find a driver for the printer locally. If an appropriate driver cannot be found, the print server generates a cabinet file (.cab file, also known as a setup file) that contains the appropriate printer driver files. The print server downloads the .cab file to the client computer. The user on the client computer is prompted for permission to download the .cab file.
6. The client computer downloads printer drivers and connects to the printer using either IPP or a remote procedure call (RPC), depending on the security zone that the printer share is in. The security zone is configured on the client computer through Internet Options in Control Panel. With a Medium-high or Medium security zone, IPP is used, and with a Medium-low security zone, RPC is used.
7. Once this configuration is done, the user can send documents to the print server.
Many major vendors have adopted the IPP standard with IPP embedded in a single physical output device - in which case clients talk directly to the printer. For example, with IPP, you can print to an IPP ready printer like Canon iR5000 series copier machine through HTTP protocol. You can also use IPP to print to a non-IPP enabled printer through a IPP gateway. It is quite easy to install IPP gateway. In Windows system, install and run Internet Information Server (IIS) on the print server. When IIS is installed on a computer running Windows Server 2003, the Internet Printing and Active Server Pages components that are necessary to enable Web-based printer management and Internet printing are not installed by default. If you elect to install the Internet Printing component when you install IIS, the Active Server Pages component will also be installed by default. This behavior is controlled by the Internet Printing and Active Server Pages check boxes in the IIS installation. Once IIS is installed on the print server, you can manage a printer from Internet Explorer by accessing the address http://printserver/printers. Basically, IPP allows the user to:
- find out about a printer's capabilities
- submit print jobs to a printer
- find out the status of a printer or a print job
- cancel a previously submitted print job
To print to the printer, use the Add Printer Wizard to add an HTTP printer using the URL http://printserver/printers/printersharename/.printer.
The idea behind the IPP is to define a protocol for end users to print over the Internet, provide users with the same printing controls and concepts that they use to print locally or to LAN-attached printers. There are two main components to IPP:
- Web-based printer management which offers the ability to administer, to connect to, and to view printers by using a Web browser.
- Internet printing which allows you to use the printer's URL to connect to a printer.
In IPP, print jobs are sent using Hypertext Transfer Protocol (HTTP), the same protocol used to connect to web pages. Unlike other printing protocols, IPP also supports access control, authentication, and encryption, making it a much more capable and secure printing solution than older ones.
As IPP transfers are made using HTTP v. 1.1, once a connection is made, multiple commands (files) can be sent over a single TCP connection. However, by using HTTP/1.1, IPP faces criticism for its protocol overloading. This allegedly makes for a more complex and bloated protocol and implementation than necessary — for example the venerable lp protocol was extended to cover the same functionality.
Anyway, the advantage of implementing IPP on top of HTTP is in the fact that the latter protocol is already well-tested on the Internet as a method to transfer files, which enables reuse of proven, well-tested and debugged client and server code.
It is a design goal of IPP to not invent new security features when existing protocols can be used. For example, the original RFC suggested authorization be done for example via HTTP's Digest access authentication mechanism or via SSL3. Encryption is not done by IPP itself either, but it may be handled by SSL/TLS protocol layer.
Because the service is using HTTP or HTTPS, this is typically port 80 or port 443. As IPP supports HTTPS traffic, communication can be encrypted, depending on the user’s Internet browser settings. IPP printing via HTTPS is offered in Windows XP and Windows Server 2003. Windows Vista and Windows Server 2008 also support IPP printing over RPC in Medium-Low security zone. IPP uses the client/server model, where the client resides in a PC or workstation and the server is embedded in a printer device or resides in a separate print server machine. The process is as follows:
1. Client will always initiates the communication with the server. The user connects to a print server over the Internet by typing the URL for the print device.
2. The HTTP request is sent over the network to the print server.
3. The print server requires the client to provide authentication information. This ensures that only authorized users print documents on the print server.
4. Once the user is authenticated, the server presents status information to the user by using Active Server Pages (ASP), which contain information about currently available printers.
5. When the user connects to any of the printers on the Internet printing Web page, the client first tries to find a driver for the printer locally. If an appropriate driver cannot be found, the print server generates a cabinet file (.cab file, also known as a setup file) that contains the appropriate printer driver files. The print server downloads the .cab file to the client computer. The user on the client computer is prompted for permission to download the .cab file.
6. The client computer downloads printer drivers and connects to the printer using either IPP or a remote procedure call (RPC), depending on the security zone that the printer share is in. The security zone is configured on the client computer through Internet Options in Control Panel. With a Medium-high or Medium security zone, IPP is used, and with a Medium-low security zone, RPC is used.
7. Once this configuration is done, the user can send documents to the print server.
Many major vendors have adopted the IPP standard with IPP embedded in a single physical output device - in which case clients talk directly to the printer. For example, with IPP, you can print to an IPP ready printer like Canon iR5000 series copier machine through HTTP protocol. You can also use IPP to print to a non-IPP enabled printer through a IPP gateway. It is quite easy to install IPP gateway. In Windows system, install and run Internet Information Server (IIS) on the print server. When IIS is installed on a computer running Windows Server 2003, the Internet Printing and Active Server Pages components that are necessary to enable Web-based printer management and Internet printing are not installed by default. If you elect to install the Internet Printing component when you install IIS, the Active Server Pages component will also be installed by default. This behavior is controlled by the Internet Printing and Active Server Pages check boxes in the IIS installation. Once IIS is installed on the print server, you can manage a printer from Internet Explorer by accessing the address http://printserver/printers. Basically, IPP allows the user to:
- find out about a printer's capabilities
- submit print jobs to a printer
- find out the status of a printer or a print job
- cancel a previously submitted print job
To print to the printer, use the Add Printer Wizard to add an HTTP printer using the URL http://printserver/printers/printersharename/.printer.
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