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Messages - michael-a

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New switches did not fix the problem. :(

I will try swapping eth0 and eth1 as the following thread suggests to solve a similar bug:,9242.0.html

EDIT: No luck, the problem remains.

Today I shortened some cables so that every connection to a switch is < 25 meters, and most are < 8 meters, but no improvement. I also connected router/switches via the "priority port" on the switches. (The manual says nothing about those ports.) No improvement.

A few people mentioned problems with these switches, so I will replace them with a different brand (sometime in next 2 weeks) and report the results here.

Are the delays also persistent when you detach the powerline connections.


I know I use a powerline connection and it works, but that's about it. Powerline isn't known for being reliable.

I would change that to, "home networking equipment is unreliable."

<rant> Over the past 9 years, we've used 7 routers of at least 5 different brands, and all have exhibited some behavior that requires them to be power cycled ~once a week. Often DNS and/or DHCP will just stop working, the Internet access will become intermittent, and/or the router's web config page will go down; etc. Various "features" on the web config pages - different features for each model - simply don't work, period.

We've had the power/dsl/cable lines checked, network wiring checked, etc. updated firmware, run through the most well-written checklists with tech support, and run through the whole remove-various-devices-and-retest-to-find-the-problem thing more times than I can remember. I've even set them up as a separate network (i.e. 1 router, 1 client, no modem or other network connections) and they STILL exhibit most of the same problems. </rant>

So I thought, why not build a Linux box to use as a router? This Zentyal gateway would be perfect if not for these random 10-15 second delays on every network function. Well, I still have to restart DNS and the HTTP proxy services occasionally, but that's MUCH better than power cycling the old routers (which would cause the whole network to go nuts because, again, some client devices are so poorly designed that they will become unstable or even hard lock if they lose network connectivity for a second; and then there are devices which become unstable in response to other devices' instability...and so on.).

Consumer network equipment is crap; IMO, if you find one of those products that works as advertised then either you fit neatly into one of their simple test cases or you're extremely lucky. Sorry I simply have no more patience left after years of having to spend 30 minutes troubleshooting, crawling around furniture, and pulling 5-10 power bricks every time the power fails.

Further, you do realize you have a knitted together network with multiple switches connected to switches, connected to switches. That is not the most ideal setup if you want to have a stable connection.

Can you give any info on distances between the switches?

What? From what I understand, switches are just supposed to relay packets between their ports according to ethernet specs. They're supposed to be chain-able. Nowadays we don't even need crossover cables because they auto-detect that. Most routers have integrated switches, which are designed with the capability to connect to other switches. Otherwise how would you use a switch in the router's internal network?

We're dealing with a building with cable modem at one end (on upper level) while we need wired connections running to various points on the lower level. Not every wall's wiring can be accessed (due to the short-sighted design IMO) so powerline adapters had to be added. They're far more reliable than wireless. I don't use them myself, they're only for some media clients and very basic PC things (e.g. email). They're fine. Occasionally, due to power outages, the powerline adapter that connects them to the home network will lose its IP address, but otherwise they just keep working.

The clients transfer files reliably at gigabit speeds (e.g. 50+ MB/second, with the large B) for 10's of GB while ping times remain consistently low...except when one of those weird delays occur. To me, this indicates that the physical connections are fine, but there's a piece of faulty equipment or some setting is low (e.g. max connections? small buffer size? etc.).

The problem persists...

I pulled one of the 2 identical network cards today and here's text from various places:

1. Removable chip (ROM?)


2. Soldered chip (CPU?)

Intel (R)

3. Silk-screened text on side of PCB

CPU: E25869 (B)

I think the model number is EXPI9301CTBLK.

This is what was purchased:

If that's not the information you requested, please tell me where/how I can find it.

Thank you for your time!

I installed Zentyal 2.2 as a gateway. Connections look like this:

  • Zentyal - Firewall, DHCP, DNS, Transparent Proxy, Antivirus
    • (eth0: dynamic, external) - Intel Gigabit CT (PCIe)
      • cable modem
    • (eth1:, internal) - Intel Gigabit CT (PCIe)
      • {gigabit switch}
        • PC #1
        • {gigabit switch}
          • PC #2
          • PC #3
          • SageTV HD300 (client) #1
          • SageTV HD300 (client) #2
          • {gigabit switch}
            • PC #4 - SageTV DVR (server)
            • SageTV HD300 (client) #3
            • {powerline ethernet (bridge)}
              • {powerline ethernet (bridge)}
                • SageTV HD300 (client) #4
              • {powerline ethernet (bridge)}
                • PC #5
              • {powerline ethernet (bridge)}
                • PC #6

The delays have these properties:

  • They last for 10-15 seconds (like a timeout?)
  • They are random. Any device, any connection. Computers, media streamers, etc.
  • They are not caused by load. Even when every other device is idle, the delays occur.
  • The ethernet lights on the affected client blink like crazy until after the delay.
  • The affected client does NOT report a problem with its network interface.
  • All other connections on the affected client continue working fine during the delay.

Accessing the Zentyal web interface (e.g. is also subject to these random 10-15 second delays.

Occasionally, DHCP will timeout, indicating that the DHCP is also subject to these terrible delays.

Sometimes my VPN connection will stop sending/receiving data for same period of time. So it also experiences these delays.

It seems the problem is either with hardware or some fundamental misconfiguration. No priority/limitation features like QoS/bandwidth/shaping are configured. The Zentyal box is not overloaded. CPU, memory, hard drive all report a decent amount of unused capacity. Maximum system load is around 0.70. No other device is trying to take over the Zentyal's IP/DHCP duties. There aren't any other routers on the network. None of the switches or clients are overheating. The Zentyal box is on a UPS and all its fans are running.

Following a hunch, the powerline adapters were unplugged from the network and their client devices were powered off. Remaining client devices still exhibited the delays.

Thinking that the ethernet adapters might be overheating (due to passively cooled video card in next slot), I added a fan to the Zentyal box and pointed it directly at the PCIe cards. The delays still occur.


traceroute says "network is unreachable"

The problem is Zentyal won't add the default gateway (from eth0's DHCP info) to the routing table. Since the routing table does not specify a route to the Internet, traceroute to an Internet IP will fail every time. If I add a known good route manually like so...

sudo route add default gw eth0

...then the Zentyal box can access the Internet until I change a setting in ebox, which then erases the default gateway and of course Internet access is lost again.

However, it would be impractical to have to fix the routing table every time I change a setting in Zentyal. Also this is only a test case: I plan to remove the router and replace it with the Zentyal box, which will then receive its IP/gateway/dns from cable modem via DHCP.

EDIT: I don't feel like doing a clean install of the Zentyal ISO tonight. The box has no optical drive and my USB creator program won't put the Zentyal ISO on my pendrive in a bootable way. There's some script errors about uninitialized strings (in a file called something like GatewayModel.rm) that I will try to report tomorrow. Is there any chance of getting an updated script or a fix submitted to Ubuntu 11.10 packages?

Clean install of Ubuntu 11.10 (x86) running Zentyal 2.0.x (no PPA)
  • eth0 {DHCP, external} -> current router ( -> Cable Modem
  • eth1 {static, internal} -> switch -> home network

From the Zentyal box's terminal, I can ping, but I cannot ping the IP's of any Internet sites. It's like there's no gateway configured. Ping says "destination network unreachable." In the Network -> Gateways section my dhcp-gw-eth0 is listed as enabled, default, and active. But nothing seems to use this gateway.

(I removed network-manager as it said it was no longer allowed to manage eth0 and eth1.)

EDIT: The routing tables are missing a gateway: ->, netmask:, flags: U, metric: 1000, iface: eth1 ->, netmask:, flags: U, metric: 0, iface: eth1 ->, netmask:, flags: U, metric: 0, iface: eth0

I tried restarting the computer. I changing eth0 to "not set" in Network -> Interfaces. Then I saved, applied changes, and reconfigured it as DHCP/external. Sure enough, the gateway shows up in Network -> Gateways but does not get added to the routing table. Why?

Other threads mention this same issue without a cause or a fix...

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