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Caching |
Connectivity |
Proxy Info |
Vary Header Info
A member connects to the America Online Internet Access Service through one of three major paths:
- AOLnet TCP/IP network
- Third party TCP/IP access provider
With each connection type, the AOL client software communicates with the AOL host complex, located in Northern Virginia, using a proprietary session protocol. Among its other features, this protocol identifies the destination service within the AOL host complex and directs data packets to the correct server.
In April 1995, access to the Internet was implemented on the AOL service using a new server called an IP tunnel (IPT). The data packets created by the client are IP datagrams encapsulated in an AOL wrapper. The IP tunnel simply removes the AOL wrapper and places the datagrams on the network. In the reverse direction, the IP tunnel appears to the Internet as a router. It accepts IP datagrams addressed to a member's system, encapsulates them, and injects them into the AOL system.
When a member initially connects to the AOL host complex, the client software receives network configuration information, including the IP addresses for the local system and for the DNS server. The member's IP address is a Dyamically Assigned Hardware Address (DAHA), which is an address that is assigned to a session. Once the session has ended, the address may be reassigned.
When a member runs the a 32-bit version of AOL under Windows 95/98 program WINIPCFG, he or she can see the DAHA listed under the AOL Adapter Interface. Other network utility programs, including tracert, ping, and netstat, also work under Windows 95/98 and show the AOL-supplied network interface (DAHA) as if it were a real physical network rather than a logical one.
All DAHAs resolved to the domain ipt.aol.com. The hostname is the numeric IP address with the initial 152. octet removed and the remaining periods converted to dashes. For example, the DAHA 152.171.155.70 resolves to hostname 171-155-70.ipt.aol.com.
When a member is using an Internet-capable version of AOL software (for example, Windows version 3.0 or higher or Macintosh version 3.0 or higher), then the client is automatically configured to have an IP address that is available for use by any other IP-based software application running on it. It is important to note that 32-bit applications require a 32-bit TCP/IP implementation that is available only in the AOL Windows 95/98 clients. Some applications do not clearly indicate that they are 32-bit applications.
AOL information providers have several options for connecting to AOL to update, manage, and provide content. There are three major connectivity methods:
- Direct Internet with optional authentication mechanisms.
- Virtual private data network (VPDN) connection: A network virtual connection tunneled through the Internet to the information provider's site. Tunneling requires a system on each end to encrypt/decrypt, date, and place headers on messages and transmit them.
- Leased line: A dedicated connection, usually used by banks and other institutions that own highly sensitive or proprietary data, or where bandwidth control is crucial.
AOL staff are available to discuss an information provider's individual needs. AOL works with information providers to customize connectivity methods so that members benefit from maximum performance when they request information.
The AOL client software is a native TCP/IP-enabled application. Consequently, it uses specific TCP/IP ports to communicate with the AOL host system. When using the software in a corporate local-area network (LAN) environment, where TCP/IP access is generally protected by a firewall system, certain changes need to be made to the firewall configuration in order to gain access to the AOL host.
Please follow the guidelines below to gain access to America Online from your corporate LAN:
- The firewall administrator must configure the firewall to allow AOL Client software within the firewall to use TCP port 5190
- 5193 for outbound TCP/IP
traffic to access the host. This is a minimum requirement that will allow basic web traffic.
- AOL recommends opening TCP and UDP ports 5190 - 5193, TCP port 443 and ICMP type-3 code-4 "Fragmentation Needed".
- Install the latest version of the AOL client software. You may download the software at http://www.newaol.com,
from Netscape or MSIE, or keyword "Upgrade" on AOL.
- Once installed, launch the application, click "Cancel" to the location-related question, and select "Setup" on the Welcome
screen. Click "Edit Location" and change the "Network" field to "TCP/IP." Click "Save" and "OK."
- You are now ready to log in to America Online.
NOTE: There are security risks associated with opening up the firewall for outbound access though ports 5190 and
443. Please notify your Network Security Administrator when accessing AOL through your corporate firewall.
A list of registered TCP/IP port numbers is available at http://www.iana.org/assignments/port-numbers
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