Network/speed significantly reduced. Why???

[Letterbox Mike]

Hopefully someone here with more IT knowledge than I have can give me some guidance here...

Today we got new internet service hooked up at our shop (went from Time Warner Cable to AT&T Uverse fiber, 4 times faster for the same price)... ATT installed the modem/router (one unit, not separate pieces of equipment), hooked it into our network and we thought all was fine. We have 6 computers plus a handful of other network devices/printers on the network.

The ATT router/modem has a 4-port switch built in. We have three of our network devices/computers hooked directly into it. The fourth port is hooked up to a 16 port switch to which the remaining network devices/computers are attached. Everything works, all computers have internet access, except my computer is seeing extremely slow network and internet speeds.

The other computers are returning between 17-19 Mbps download speeds on speedtest.net, while my computer is returning between 1 and 2 Mbps. I ran an LAN test writing a 100mb file across our network to our network-attached drive and got an average write speed of around 80-85 mbps on other computers and 5-7 mbps on my computer.

Thinking it was the physical connection between my computer and the network gear, I tried connecting my computer to the ethernet cable of another computer in my office (that was known/tested to be operating at the proper speed). Same thing, super slow. So I guess that means the problem is physically on my computer.

So I tried updating the driver for my ethernet port but it's up to date (the computer is only a month or so old). Beyond that I have no idea what to even consider. No software was installed on my computer, no changes to it were made in any way. We disconnected the old TWC internet back at the network rack, hooked up the new AT&T gear and that was it. My computer wasn't touched. Prior to the service changeover, my speeds were normal. I ran a speed test on the internet connection and returned exactly what I was expecting. I never checked my LAN speed but I can say with certainty that it was working fine, the speed I'm seeing over the network is almost unusable.

What am I missing?

 

[choucove]

It might help to find out if your computer (and likewise the other workstations that are running at the higher speeds) are plugged into the switch or the gateway. For instance, if yours is the only workstation connected directly into the back of the gateway router instead of into the switch, perhaps reconnecting your computer into the switch will fix the issue or vice versa.

 

[Letterbox Mike]

It might help to find out if your computer (and likewise the other workstations that are running at the higher speeds) are plugged into the switch or the gateway. For instance, if yours is the only workstation connected directly into the back of the gateway router instead of into the switch, perhaps reconnecting your computer into the switch will fix the issue or vice versa.

Mine is connected directly to the gateway, I tried flipping it to the switch with no change. The other computer's network connection I tried (and which gave me the same slow speeds on my computer but the correct speeds on it's "normal" computer) is connected to the switch.

I have not tried running ALL network devices through the switch and having nothing else run through the gateway, I didn't think it would make a difference but maybe it would?

 

[ddarlak]

my best hack guess is you are having an ip conflict somewhere along the way. anytime there is no reasonable answer it always ends up being an assigned ip that farkes it up. i have given up on my DHCP and assigned everything a static address and haven't had problems since....

my knowledge on this is only based on beating my brains out trying to figure out my own network problems......

 

[Letterbox Mike]

my best hack guess is you are having an ip conflict somewhere along the way. anytime there is no reasonable answer it always ends up being and assigned ip that farkes it up. i have given up on my DHCP and assigned everything a static address and haven't had problems since....

my knowledge on this is only based on beating my brains out trying to figure out my own network problems......

I assumed it was something like this too, but it's still strange that it's happening only on one computer and everything else is working properly... And unfortunately my knowledge of all things IT are extremely limited to say the least, so I can develop a "concept" of the problem but actually figuring it out is not likely without leaning on people that actually know what they're doing.

 

[ddarlak]

i had a problem that came out of the blue about a year ago, my PC and one of my internet camera's were getting issued the same ip address once in a blue moon, then one of my printers would crash, i'm assuming because the info wasn't getting to the printer in time and it timed out. i finally went static and the problems went away. took me forever to get past the concept stage, and i still have theory issues with understanding all that goes into networks, but the static thing made my life easier....

 

[Letterbox Mike]

i had a problem that came out of the blue about a year ago, my PC and one of my internet camera's were getting issued the same ip address once in a blue moon, then one of my printers would crash, i'm assuming because the info wasn't getting to the printer in time and it timed out. i finally went static and the problems went away. took me forever to get past the concept stage, and i still have theory issues with understanding all that goes into networks, but the static thing made my life easier....

I had actually ordered static IPs for the new service but when they installed it the service was activated as dynamic. I didn't realize that at first and was originally thinking the problem was due to the static IPs, but your experience is making me think maybe something similar is happening. But I'm not sure if that would explain why I still have an internet connection, albeit a slow one, but it seems if an IP wasn't being assigned correctly I wouldn't have a connection at all. But I wouldn't really know, I'm talking out of my butt right now...

 

[jtrainor56]

Check the network adapter and see if it is set on auto or 100 full. Should be auto but try changing it to see what happens. Is your pc plugged into the 16 port switch, might be a bad port.

 

[Techman]

Turn off AVG. Especially for network and internet access.

 

[Letterbox Mike]

Turn off AVG. Especially for network and internet access.

Don't run it anyway. As far as I can tell my computer is set up the same as every other machine in the shop. They're all running Windows 7 and it's Microsoft security software using the default settings...

Ugh.

 

[ddarlak]

Two network components can have the same ip address and work, but they will collide and cause problems.

Try your computer static and see if it gets better.

Here are the steps to setting your pc/network static:

First run cmd on your computer, then type ipconfig /all

Copy down your subnet mask,default gateway & dns servers.

Enter your router through a browser, should be same address as default gateway, example: 192.168.1.1

Turn off your DHCP, choose static.

Right click your network connection, goto properties, highlight internet protocol version 4, click properties.

Change to: use the following ip address.

Choose an ip address for your computer, example: 192.169.1.120

Fill in the rest of the info from what you copied down before.

Reboot everything. If it works and you want to make your network static you will have to give everything a static ip address manually.

 

[Letterbox Mike]

Ddarlak, I was digging around in the router control panel looking for that setting but I can't see anywhere where it allows you to change from a DHCP ip to a static ip. Maybe I'm not looking in the right place.

Interestingly, I did just reconfigure the wiring arrangement at the network rack. All of our network devices are now running through the switch, nothing is connected directly to the gateway (originally my computer and 2 other devices were run to the gateway, everything else through the switch). This increased my internet speed a little bit, up to around 5-6mbps, still significantly slower than every other machine in here (which are all still returning 17-18mbps), but it is an improvement. The LAN speed test showed a very minor improvement as well, but almost nothing, about a 1-2mbps improvement. Interestingly, last night I tried only removing my computer from the gateway and running it through the switch and that made no improvement, but by removing everything from it the speed increased... WTF?

 

[signswi]

If you really want a speed boost you can put the IP to computer name resolutions directly into your hosts file for all your internal computers. That's not the issue here, I agree it's probably an IP conflict, but thought I'd throw it out there in case it helps anyone as name resolution is a decent amount of network overhead.

insignia, what model(s) of switch and router?

 

[signage]

You need to log into both your router and your switch and see the list OF address each has assigned. Now look for any that are the same. Have you contacted AT&T about this issue? You may want to d that and see what they find.

 

[ddarlak]

Ddarlak, I was digging around in the router control panel looking for that setting but I can't see anywhere where it allows you to change from a DHCP ip to a static ip. Maybe I'm not looking in the right place.

should be under setup>internet setup - what router is it?

but by removing everything from it the speed increased... WTF?

this makes it definitely sound like your having a ip sharing issue.

unless...

have you been using the same cable to hook up this computer each different time you've changed it? you could have some crazy crossover cable causing a slow down. i also had this happen where i had an old cable and it was only giving me 54Mbps instead of 100Mbps the other computers on the network were getting. now my test speed on the other computers was about 18Mbps, but i was only getting 3Mbps on my system, this sounds kinda what your getting....i changed the cable and the adapter reported a 100Mbps connection and my test was 18Mbps like the other computers....

 

[Letterbox Mike]

Update... I'm pretty sure my network interface card on my computer is causing the problem. It's stuck at 10mbps no matter what I do. I've tried forcing it and the gateway to 100mbps and 1gbps, it remains at 10 on my computer. I've run a brand new ethernet cable directly from the gateway to my computer and through the switch to my computer, bypassing all wiring in the walls here and it remains 10. Upon connecting my network jack in the wall to the other computer in my office, that computer defaults to 1gbps, so the problem is not wiring or the actual cat5e cable, but the network adapter on my end. The next logical step is to just go to Best Buy and buy a new NIC and see if that solves it...

 

[Letterbox Mike]

Update, got it figured out. So simple it's stupid. Unplugged the computer, held the power button down to discharge any static in the machine, plugged it back in and we're up and running. That's all it took. Unbelievable...

Thanks everybody!

 

[signswi]

Basically you cold rebooted which caused your router to reassign your mac address, so it was an IP conflict.

By the way "discharging static" didn't do anything in relation to this problem . It's also not static it's charged capacitors that you are discharging when you hit power with an unplugged machine as the machine tries to draw power to start and empties the caps. That's really only necessary before you pop the case open to change out parts as you're preventing those capacitors from discharging at the wrong time while you're working and shorting something.

 

[Letterbox Mike]

Basically you cold rebooted which caused your router to reassign your mac address, so it was an IP conflict.

By the way "discharging static" didn't do anything in relation to this problem . It's also not static it's charged capacitors that you are discharging when you hit power with an unplugged machine as the machine tries to draw power to start and empties the caps. That's really only necessary before you pop the case open to change out parts as you're preventing those capacitors from discharging at the wrong time while you're working and shorting something.

Good to know!

 

[anotherdog]

Update, got it figured out. So simple it's stupid. Unplugged the computer, held the power button down to discharge any static in the machine, plugged it back in and we're up and running. That's all it took. Unbelievable...

Thanks everybody!

This happens to us all the time, With a number of wired and wireless computers joining and leaving the network during the work week, IP conflicts creep in and packet collision cripples speed.

Every couple of weeks I shut the network and computers down and restart (network, then computers) so the router can assign new IP's to all the machines. This pretty much cures the slow network, especially when I didn't change anything in the system.