Trendnet TS-S402 2-Bay SATA I/II Network Storage Enclosure Review

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Jim Buzbee


Trendnet <nobr>TS-S402</nobr>

At a Glance
Product Trendnet 2-Bay SATA I/II Network Storage Enclosure (TS-S402)
Summary Two-drive Network Storage Device with gigabit capabilities and BitTorrent support
Pros • Compact
• Gigabit Ethernet
• Multimedia server
• Integrated Bittorrent client
• Relatively inexpensive
Cons • Noisy
• No client backup software
• Can’t back up to external or networked drives
• No power save features

The Trendnet TS-S402 is a Bring Your Own Disk (BYOD) RAID-capable NAS that supports either one or two SATA drives in a very compact 4.7 x 7.9 x 4.7 inch chassis. Along with its RAID capabilities, the S402 supports gigabit Ethernet, media- serving capabilities and dual USB ports for print serving, backup or external storage.

Like most NASes, physical setup consisted of not much more than connecting the Ethernet and power cables and plugging in drives. The front of the product has a swing-open door for users to install their SATA drives. The door itself felt a bit on the flimsy side, but you won’t be needing to access it much after initial disk installation.

Drive mount on no-frills brackets; just two bent-metal pieces that screw onto the drive sides. You manually plug the SATA data and power cables into the drive and need to work the cables a bit in order to close the front door. For the purposes of this review, I was supplied with a unit pre-configured with two 80GB Western Digital drives, so didn’t have to go through the installation process.

As seen in the photo above, the front panel contains a row of status LEDs, a “USB backup button” and a USB 2.0 port. The back of the unit, shown in Figure 1, has another USB port, power button, gigabit-capable Ethernet port, power connector, reset button and fan vent.

Back Panel

Figure 1: TS-S402 Back Panel

As you can see in the photo, the fan vent is fairly large, which usually means quiet operation. But unfortunately, the S402 makes a bit more noise than I like to hear in these types of boxes. For power-usage, I measured a draw of around 18 Watts both when in use and after the unit had stood idle for a while.

Trendnet supplies a Windows-only installation CD that is used for the initial configuration. The basic purpose of the installation is to locate the device on the LAN and do the initial setup. The S402 comes with a hard-coded IP address of instead of being configured to grab its IP information via DHCP. So, depending on your network configuration, locating the device may be a bit of a challenge, as I found in Figure 2.

Detection failure

Figure 2: TS-S402 Detection failure

The installation documentation was a bit weak in this area. But after a couple of false starts, reboots and directly connecting to the NAS, the setup software finally located the S402 and brought up an attractive interface as shown in Figure 3.

setup utility

Figure 3: TS-S402 Setup Utility

Most of the configuration buttons in this interface spawn a web browser to connect to the device where the real setup is done. So if you’re a Apple or Linux user like me, you can turn back to your preferred operating system for the remaining configuration.

Feature Tour

Figure 4 shows the main web-based configuration screen that I found to be fairly attractive, responsive and easy to use although a few of the menus were a bit misdrawn using Safari under OSX. Note that the web-configuration menu is only accessible through HTTP, not the more secure HTTPS.

Main Menu

Figure 4: TS-S402 Main Menu

From these menus, basic network configuration such as IP address, netmask, DNS info can be set, the administrator’s password changed, the system can be rebooted, etc. While setting up the network, I noted that the S402 does not support jumbo Ethernet frames. Figure 5 shows one of the basic setup menus where a number of configuration items are available.

Basic Setup

Figure 5: TS-S402 Basic Setup

From this menu, you can see where the Windows workgroup name can be specified, the web port can be changed, a NTP server can be specified, etc.

Along with the basic setup, a number of more interesting features can be turned on and off. Figure 6 shows the “Server Preference” where these services can be activated.

Server Preference

Figure 1: TS-S402 Server Preference

This mens shows standard support for Windows file sharing using Samba, FTP server support and NFS support. It’s good to see support for NFS which is a file-service protocol natively used under Unix-type machines such as Linux and OSX. Unfortunately, the use of NFS requires the client to know the full path of the remote share on the server side and Trendnet does not document this.

But recently, I learned a new method of getting this path. The showmount -e <ip-address> command issued from a Unix command line will let you query remote servers to find out the full path of shares. Once I used this, I was able to NFS mount shares on the S402.

Media Services

The other services listed in this menu are used for serving multimedia to your network. If you have a compatible client device, a UPnP AV server can stream music, videos and pictures on your network. Figure 7 shows the setup menu for the UPnP AV server.

UPnP Setup

Figure 7: TS-S402 UPnP Setup

My tests of this server showed it to work, but its functionality was a bit limited. All of my multimedia was presented in a single list instead of being segregated by music, pictures and video. And, as is the case with all of this type of usage, the supported multimedia formats depends on what type of UPnP client you have on your network.

The other server supported is an “iTunes Server”. So if you run iTunes on your computer, you can have the S402 serve up music for you. Figure 8 shows a screen-grab of a portion of my iTunes application where the S402 server is shown.

iTunes integration

Figure 8: TS-S402 iTunes integration

My tests showed this worked fine with standard mp3s and with DRM-restricted music purchased through the iTunes music store. As you can see in this figure, album-art was also supported.

Another interesting feature of the S402 is BitTorrent support. You can upload a BitTorrent file and have the S402 handle the download for you. Figure 9 shows a BitTorrent download status menu.

Bittorrent Status

Figure 9: TS-S402 Bittorrent Status

My tests of this capability showed that it worked fine, although the status menu was a bit sparse, lacking fields like number of seeds, number of peers, estimated time to completion, etc. I find that NAS devices and bittorrent clients are a good fit, especially for jobs that require multiple days to finish. Fire up a torrent, walk away and let it do its thing in the background.

Another interesting menu found under the configuration section was “Remote Package” which appears to be a method to add software to the box, although I found no documentation on the feature or any packages on the Trendnet web site.

Share Management

Of course, the main purpose of a NAS is to share data on the network. Figure 10 shows the Share setup menu.

Share Setup

Figure 10: TS-S402 Share Setup

Options are provided for specifying the share name, disk used, and protocols allowed to access the share. The disk specification did not include USB disks, which automatically get shared.

My tests of the share creation capability showed it worked as designed, but as noted previously, it was up to be to figure out the path to the share for NFS usage. And as I’ve seen before, NFS usage under OSX can be a bit of a pain because most NFS servers don’t like using the high ports that OSX calls for.

You can also see a choice of "Private" or "Anonymous" for the share. When “Private” is selected, you are given the choice of which users are allowed to access the specified share. For creating users, a basic menu is provide as shown in Figure 11

User Creation

Figure 11: TS-S402 User Creation

I found it interesting that an error was thrown if I used a password greater than 8 characters on this menu. Note that the S402 provides no group capability for classifying sets of users together.


NASes are often used for network backup of other devices. So many manufacturers supply client software to back up data to the NAS. But Trendnet doesn’t bundle any client backup software. But it does provide the ability to back up one share to another on the device. Figure 12 shows the menu that allows users to schedule these backups.

Backup menu

Figure 12: TS-S402 Backup menu

Note the extensive options for specifying when the backups should occur. It was interesting that neither the source nor the destination folder could be an external USB or networked drive, which would seem to be an obvious choice.

My tests of this capability showed it worked, although when I set it to back up every hour, the backups didn’t seem to occur that often.

Disk Management

Trendnet provides a number of capabilities for managing the disks in your S402. Figure 13 shows a Status menu displaying various information regarding the disks installed. The “Health Test Result” menu seems to imply the presence of SMART diagnostics.

 Disk Info

Figure 13: TS-S402 Disk Info

I didn’t find any method to set the spin-down time for the drives in any of the menus. In my house, most of the time my NAS devices are idle. So it’s nice to have a method to tell them to spin down, reducing both power and noise.


As mentioned previously, the S402 supports various RAID modes. Figure 14 shows the menu where the mode can be specified.

RAID Specification

Figure 14: TS-S402 RAID Specification

In this case, I have the device configured in RAID1 mode where data is mirrored to each drive to protect against disk failure, the downside being cutting my total disk capacity in half. As you can see, the other RAID modes supported are 0, where the data is spread across two drives for additional performance but no fault-tolerance, and JBOD where the two drives are just logically combined to look like a big single drive.

When problems do occur in the system, the S402 has an email-alert mechanism so that you can get notified of the failure. Figure 15 shows the alert setup capabilities found somewhat incongruously in the “Remote System Log” menu.

Alert Setup

Figure 15: TS-S402 Alert Setup

To test the RAID recovery feature and the alert mechanism, I opened up the case and yanked the cable off one of my two drives. I expected to see some immediate reaction, but I saw nothing. Even the two disk LEDs remained lit. When I checked my email, I had nothing, but a check of the logging feature of the box (Figure 16) showed that the removal had been detected.

Disk Failure

Figure 16: TS-S402 Disk Failure

While the disk was out, I could access my data as if nothing had happened, which is the benefit of using RAID 1. To check out recovery, I shut the system down (since hot-swapping is not supported), re-plugged the drive and powered the system back up.

Once again, I had to dig a bit to find out what was going on. Figure 17 shows the log that indicated that the drive rebuild was automatically started and underway.

RAID Recovery

Figure 17: TS-S402 RAID Recovery

While the rebuild was underway, my data was available as before, but with reduced performance. It was nice to have the automatic rebuild, but I expected to get more notification, e.g. blinking lights, buzzers, or email (more on this later) telling me that something had gone badly wrong. Since I only had 80GB disks in the system, my rebuild time was fairly short – about 30 minutes.


The utilities at SmallNetbuilder’s web site can generate an almost infinite variety of performance charts but to give you a head-start, I generated a few myself, with some other BYOD two-drive NAS devices. I chose the Qnap TS-209, D-Link DS-323, and ZyXEL NSA-220 with the products configured in JBOD mode. The TS-209 is a higher-end unit than the others, but I threw it in just as a relative comparison.


  • The maximum raw data rate for 100Mbps Ethernet is 12500 KBytes/sec (12.5 MBytes/sec) and 125000 KBytes/sec (125 MBytes/sec) for gigabit
  • Firmware version tested was 1.00.17
  • The Western Digital drives supplied by Trendnet were a WD800AAJS and a WD800JD
  • The full testing setup and methodology are described on this page

100 Mbps Write

Figure 18: TS-S402 100 Mbps Write

100 Mbps Read

Figure 19: TS-S402 100 Mbps Read

1000 Mbps Write

Figure 20: TS-S402 1000 Mbps Write

1000 Mbps Read

Figure 21: TS-S402 1000 Mbps Read

You can see that, overall, the Qnap TS-209 is faster than all the low-end NASes. And also in general, the S402 seems to fare poorly in writes and do somewhat better comparatively, with reads.

Under the Covers

Figure 22 shows the main board of the S402.

Main Board
Click to enlarge image

Figure 22: TS-S402 Main Board

As you can see, the main processor chip is covered, but Trendnet documents it to be a Marvell 88F5182 Orion processor. a popular NAS System-on-Chip (SoC). This SoC is an ARM-based and includes SATA support and USB 2.0 ports. The 10/100/1000 Ethernet port is via a Marvell 88E1118. As mentioned earlier, Trendnet has chosen to not enable jumbo frame support.

The S402, like most other consumer-level NASes, runs Linux. Trendnet even mentions a Linux kernel version number on its web site. But to check it out at a deeper level, I started my usual poking around.

First, I attempted to figure out a way to make the top-level directory sharable so that I could see the entire operating system structure. To do this, I intercepted the share creation arguments using argument-modifying http proxy and modified the share. This failed and thew an error. Trendnet was apparently checking the arguments on the server-side as they should be.

So, I had to turn to a different mechanism. One common flaw I find in consumer NASes is in the handling of the alert email address. All too often, whatever you pass in gets blindly sent to a script that sends out the email. To see if the TS402 was susceptible to such a hole, I modified my email address to add a command, bracketed in back-tics as shown in Figure 23. If this were accepted and passed on, my “” script would get executed when email was sent.

Hacking the alert mechanism

Figure 23: TS-S402 Hacking the alert mechanism

In my script, I first executed a simple “ps” command with the output redirected to a file to show all running processes. Then I did a recursive listing of all files on the system, once again with the output redirected to a file.

My next problem was getting the box to send email since there was no “test” button that I usually like to see. Up to now, I hadn’t gotten any email so I didn’t know under what circumstances email would be sent. If anything, email should be sent when a disk fails, so once again I yanked the cable from a drive. And when I went back to see if my new files had been created, voila!

From here it was a short path to take complete control of the S402. First I searched for a telnet daemon and found one in the /usr/sbin directory. Then I modified my script to fire it up, and when I yanked a drive again, I was in. (Figure 24)

Telnet Access

Figure 24: TS-S402 Telnet Access

Getting root access was as easy as issuing a su command, since the root account had no password! As I poked around I saw a number of interesting things. First, the S402 appeared to have 64 MB of RAM instead of the 32 listed on Trendnet’s web site. And the Linux kernel was version instead of a 2.4.25 kernel as listed in the specs.

A list of the running processes showed an undocumented rsync backup daemon running. Rsync is a nice feature to have, but it really needs to be configured properly. A quick rsync test from my Mac showed that it would give read and write access to all the files on a share, from any box on the LAN no password required. Oops! Definitely something good to know.

More poking around showed that the iTunes support was via Firefly and that it was running a broken configuration web server on port 3600 with an admin password of 111. The UPnP A/V support was provided by uShare. Digging around the log files showed why my email alerts were failing. The following error message was found in a system log:

<root@nas> sender rejected : invalid sender domain <root@nas> sender rejected :
invalid sender domain 

Evidently Comcast, my ISP, didn’t like the way the S402 was sending email (with an invalid domain name) and rejected its attempt. Poking around more showed a standard set of utilities such as Samba, busybox, boa, etc. With all of this GPL software in use, Trendnet is bound by license to priovide source code, but I could find none on either the web site or on the delivered CD. Hopefully this was an oversight by Trendnet that will be corrected soon.

Closing Thoughts

The S402 is a decent NAS with a street-price as low as $170, which is about the same price as the, Dlink DNS-323 and a bit cheaper than the $210 ZyXel NSA-220 I reviewed recently.

All three of these products are based around a similar Marvell chip and design. Feature-set wise, the S402 lacks jumbo Ethernet frame support and doesn’t include a backup software package. But otherwise is similar to these other entry-level NASes.

As for build-quality, the S402 didn’t seem nearly as solid as the NSA-220 and was noisier to boot. And for performance, the S402 lags a bit behind both the ZyXel and the DLink and is far behind more expensive dual-drive NASes that tend to be in the $350 neighborhood.

Although the S402 has some nice capabilities, it has bugs and little to make it stand out from the crowd. So if you’re looking for a low-end, dual-drive, BYOD NAS, I’d recommend considering either the D-Link DNS-323 or ZyXel NSA-220 before the S402.

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