Blog: Linksys

I had bought a new Wireless HP Laserjet printer and connected it to my wireless router.  Print jobs tested from wireless devices on the same subnet worked flawlessly.

Next, I needed to be able to print from my PCs directly outside of the wireless router.  A brief overview of my network at home is:

Cable Modem -> Cisco 851 Router (hardwired PCs, IP Phone, VPN) -> Linksys E4200 Wireless Router (Laptops, Printer).

I configured port forwarding on the wireless router to forward port 9100 to the printer’s IP address.  I setup a new network printer and told it to use the IP address of the outside interface on the wireless router.  The printer started printing, but then it would not stop.  The PC kept sending the job over and over, and it would never clear out of the print queue. [more]

Within the ports tab of the printer properties on my PC, I had to uncheck “Enable Bi-Directional Support”.  Bi-Directional printing can allow the printer to communicate back to the PC to tell it that the print job has completed.  Turning this off tells the PC to send the job to the printer and then remove it from queue

A network support customer with DSL had lost Internet access over the weekend.  They tried rebooting the DSL modem and Linksys WRT54G router to no avail.  When I got onsite, I connected to the router’s wireless as well as Ethernet port with my laptop and confirmed that there was no Internet access.  I connected to the web management interface of the router which had a complex password, so the customer likely had not gone in and changed anything. 

I could see that the router had successfully obtained a public IP address, gateway, and DNS servers from the ISP.  There was an internal ping utility built into the router, and I was able to use it to successfully ping the DNS servers and gateway IP addresses.  When I tried from the connected PC, I could ping the router’s public interface, but not the gateway of the router or the DNS servers. 

I looked through the settings to see if I could find any reason that traffic was dying going through the router and could not find anything.  I then backed up the configuration of the router to my laptop and did a factory reset.  After the router came back up, I was able to access the Internet through the router and ping everything.  [more]

I uploaded the configuration file back on to the router and it broke the connection again.  I decided at this point to factory reset again and manually set the password and SID on the unit back to the previous settings.  It is my guess at this time that the configuration on the router had become corrupted.

The setup documentation, on the CD that is in the box and the website, for the Linksys SRW2024 switch instructs users to use a baud rate of 19,200 to connect to the console. Upon connecting at the rate everything in the console looks like gibberish. Connecting at 38,400 opens the telnet session properly and allows access to the configuration. I verified in the settings that the baud rate is set to 38,400. Luckily I did not follow my initial thought that the firmware was corrupt.

The new business class Linksys router (RVS4000) has lots of great features (very much like Cisco’s IOS).  I was recently setting one up for a customer that had an SBS server and a Symantec mail appliance.  The SBS server was not going to use ISA so I needed to set up a VLAN on the Linksys for the DMZ.  This was all easy enough, but when it came to publishing ports, I ran into a limitation in the configuration interface.  I needed to publish RDP (TCP port 3389) directly to the SBS server on the main/default VLAN, and SMTP (TCP port 25) to the mail appliance on the DMZ VLAN.  Unfortunately, the web interface for configuring port forwarding on the Linksys only allows you to modify the last octet of a published address (pre-filling the first three octets from the default VLAN).  [more]I did some research and even called Linksys support, but this is “by design”.  I tried exporting the config to see if I could change the publishing definitions directly and just re-import, but the config also only saved the last octet.  I was able to work around this limitation by spliting their class C in half (255.255.255.128 as the subnet mask) and using the lower half for the internal LAN, and the upper half for the DMZ.  This way, I was able to publish ports on the two separate VLANs, but still have the traffic segmented.