Overview

The Netgear DG834G is a combined DSL Modem, NAT Firewall/Router, 4-port 10/100 Ethernet Switch and 802.11b/g Access Point housed in a rather large (26cm x 17cm) plastic case. The device can be wall-mounted to improve WLAN range, and an external antenna can be connected if needed.

Internally, the DG834G contains a 150 MHz MIPS 4KEc CPU running Embedded Linux, the source code for which is available here.

Note that the D-Link G604T uses the same CPU and OS, so it most likely has very similar features and performance.

Setup and Configuration

All Setup and Configuration is done via a Web Browser, and entering the ISP service details was quick and easy. Once the DSL connection was established, all the private machines on the 192.168.0.x LAN had Internet connectivity and no further LAN configuration was required. The next step was to configure the WLAN interface and this is where the limitations of the browser-based interface first became apparent. I run my WLAN as an open network and use only MAC-address access control. The only way to enter the needed MAC Addresses and Device Names was to type them into the web page individually and to then click an Add button to store each entry. This method does not scale well and is tedious and error-prone; transferring the needed details via a text file would be much faster and more accurate.

Performance

Initial tests showed that LAN performance was good, and that the device had no problems saturating my (rather slow) 256/64 DSL link. Performance was clearly superior to that of the USB-based DSL Modem described here. Performance of the 802.11g WLAN interface was also good and a range of over 20m was easily achieved with a simple 4 dBi omni-directional antenna.

Supported Applications

Several networking applications were tested on the private machines, and most were able to communicate over the Internet without problems. However, there was one notable exception:

Microsoft VPN connections to an external VPN Server could not be established.

Limitations

The most immediately obvious limitation of the device is the lack of flexibility of the supplied browser-based user interface. Given that the device is running Linux, most users would expect many more features to be available than are exposed by that interface. For example, when things go wrong, one of the first things the user would want to do is monitor network traffic. Linux has excellent support for this, but the vendor chose to not provide this capability. If a traffic monitor were available, the user could quickly determine the cause of a whole range of simple problems and then take corrective action like adding a needed port mapping or similar.

Without a traffic monitor, the only other option is to search the vendor's support site and hope that a fix for the problem is available. Luckily, in the case of the VPN problem, the search produced quick results: the problem had been discovered early in the product's life-cycle and a firmware patch was available. The patch was downloaded and installed without problems.

Further testing showed several additional limitations of the device:

• The LAN and the WLAN are bridged internally, meaning that the IP network address (default 192.168.0.0) is the same for both networks. This means that the WLAN machines and the LAN machines cannot easily be isolated from each other, as they are all directly reachable and their traffic does not traverse the built-in firewall.
• Only a limited form of permanent port mapping is supported. While so-called Service Entries can be added to an internal table, it is not possible to map an incoming port number to a different target port number on a private machine.
• There seems to be no way of making an Internet IP address available for use on one of the internal machines (Address Redirection). Without such a facility, all your computers will have only address-mapped Internet access, and only the Router itself has unmodified Internet access. Software Routers such as NAT32 allow the Internet-connected machine on which they run to retain totally unmodified Internet access, which means that all NAT-hostile applications will at least run on that machine. Fortunately, most software vendors are now designing applications with NAT compatibility in mind, and the few remaining NAT-hostile applications (e.g. NetMeeting) are gradually becoming obsolete.

Enable the Telnet server on the device by clicking this link: http://192.168.0.1/setup.cgi?todo=debug
Then start a Telnet client via this link: telnet://192.168.0.1
You can then issue a small set of BusyBox commands to a shell.
Further details about Embedded Linux running on the DG834G can be found here.

Summary

The DG834G is definitely a useful device with good performance and an adequate set of features for a small home network. However, in terms of flexibility and capability, it cannot compete with software-based routers like NAT32, which support traffic monitoring, access management, multiple private networks, multiple Internet interfaces, several types of port mapping, a powerful scripting language (Tcl) and a CRON daemon. Ironically, many of these features are available in Embedded Linux, but the vendor has chosen not to provide them in this product.

Interestingly, many DSL Router owners also run NAT32 on one of their internal machines, thus making many of the above features available on their private networks.

Additional Notes

Here are examples of how to send commands to a Netgear DG834G Router at address 192.168.0.1. For other IP addresses and router types, please modify the input values before clicking Send...

For details about other Routers, please see OpenWRT and Seattle Wireless.

SEE ALSO

USB DSL Modems
D-Link DSL-G604T