[Solved] Wired connection trouble on Linux PC

Author	All Replies
timcuth Braves Fan Premium join:2000-09-18 Pelham, AL Reviews: ·AT&T Southeast 1 edit	[Solved] Wired connection trouble on Linux PC I am having a lot of trouble with the wired ethernet connection on my Linux PC. It is not distro-specific, kernel specific, or driver specific. I have had a lot of trouble with the Linux driver in the past, but I am beginning to suspect a hardware problem. The connection is established, but the speed varies between 390 kb/s and 800 b/s (bits, not kbits). The connection slows down and speeds back up fairly regularly. Wireless connections are fine. There is only one other wired connection in the house, my wife's Win7 PC, and it does not have this problem. So, I do not suspect a DSL problem or a router problem. The ethernet controller is on the Gigabyte motherboard. It is a "Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI Express Gigabit Ethernet controller (rev 06)". I have Ubuntu 11.10 and 12.04, and Sabayon 8 and Arch Linux installed on the PC. All of these distros are using different kernels. On Ubuntu 12.04, I installed the driver from Realtek, r8168 instead of r8169. This usually fixes any of my connection problems, but this time it did not. I have tried powering down the PC and disconnecting it from AC power. It does not help. There is a bug on Launchpad, #998200, which seems to be the same problem I am having. One guy says his connection only works after installing a network backports package (or powering down and disconnecting from AC). I installed the network-backports package on my Ubuntu 11.10, after which I could not connect at all. I uninstalled the backports and now I can connect again, but it still has these drastic slowdowns. I am just about out of ideas, except for the idea of buying a new ethernet card. Tim -- "Life is like this long line, except at the end there ain't no merry-go-round." - Arthur on The King of Queens ~ Project Hope ~
	to forum · permalink · 2012-05-21 08:56:04 ·

rexbinary Mod King Premium join:2005-01-26 Plano, TX	Re: Wired connection trouble on Linux PC How are you measuring the speed? Is this when communicating with other PCs on the network or to the Internet?
	to forum · permalink · 2012-05-21 08:58:32 ·
timcuth Braves Fan Premium join:2000-09-18 Pelham, AL Reviews: ·AT&T Southeast	I see the speeds when I am running the package managers of the distros. These display the momentary download speed, updated every few seconds. However, it is noticeable when doing ordinary web browsing, although that does not display speed statistics, just big lags in loading web pages. Tim -- "Life is like this long line, except at the end there ain't no merry-go-round." - Arthur on The King of Queens ~ Project Hope ~
	to forum · permalink · 2012-05-21 09:02:04 ·
pablo MVM join:2003-06-23 kudos:1	reply to timcuth Hi timcuth , Given NIC's are so cheap, why not get a new NIC (different variety of course! and disable the on-board NIC. For 20-odd bucks, you can do-away with your problem. Recently I was troubleshooting my son's NIC as it was behaving erratically. Finally, I said to myself, why am I wasting so much time on this (aside from being stupidly stubborn! , I picked up a new NIC, disabled the on-board NIC and bam! no more problems. Another point of reference: a neighbor and I started a non-profit WISP a while ago. This gave me exposure to all sorts of weird-ish hardware issues related to lightening and/or power surges. I had a NIC on a router which would work well for a 10-15 minutes, then mangle packets and wreck havoc on the network. It would periodically do this so it drove us bonkers! Given the number of devices on the network, it took some sleuthing but I nailed it. The point is, some times it's easier/cheaper/faster to swap in new hardware than to deal with non-deterministic hardware issues. Cheers! -pablo -- openSUSE 12.1/KDE 4.x ISP: TekSavvy Bonded DSL; backhauled via a 6KM wireless link Assorted goodies: »pablo.blog.blueoakdb.com
	to forum · permalink · 2012-05-21 10:30:56 ·
Bink Villains... knock off all that evil join:2006-05-14 Denver, CO kudos:4 Reviews: ·VOIPo 1 edit	reply to timcuth Have you tried swapping out the CAT5 cable with a known good one? Akin to what pablo mentioned, this is a VERY inexpensive way to troubleshoot problems with a cable.
	to forum · permalink · 2012-05-21 10:45:40 ·
rexbinary Mod King Premium join:2005-01-26 Plano, TX Reviews: ·Verizon FiOS	reply to pablo said by pablo: Given NIC's are so cheap, why not get a new NIC (different variety of course! and disable the on-board NIC. For 20-odd bucks, you can do-away with your problem. Great idea. One thing to watch for though is the last time I went shopping for NICs, 99% of them used realtek chips. -- Verizon FiOS subscriber since 2005 \| Mac owner since 1990 \| Fedora user since 2006 \| CentOS user since 2007 \| "Anyone who is unwilling to learn is entitled to absolutely nothing." - graysonf \| EDIT: I seldom post without an edit.
	to forum · permalink · 2012-05-21 11:03:54 ·
timcuth Braves Fan Premium join:2000-09-18 Pelham, AL Reviews: ·AT&T Southeast	reply to timcuth Thanks. I haven't messed with the cabling for quite a while, I'm not sure I understand why it might have gone bad. But I will try changing it and see what happens. I was looking at new NIC's, yesterday. If I buy a new one, I will get an Intel Pro. But, when I shopped at NewEgg.com, there are so many varieties of Intel Pro 10/100/1000, I have no idea why I would choose one or the other. Tim -- "Life is like this long line, except at the end there ain't no merry-go-round." - Arthur on The King of Queens ~ Project Hope ~
	to forum · permalink · 2012-05-21 11:16:30 ·
pablo MVM join:2003-06-23 kudos:1	Howdy, I re-read your post and I realize that one thing you'll want to do before picking up a new NIC is test the port on your router. Given you have a known-good port, hook into it and re-run your test. See if all is well. Do not use another random port on the router (unless you've previously tested it ... ... I've found is if one port goes bad on a router, the circuitry within it is such that there's typically a companion port which is also affected. For example, if port 1 goes bad on a four port switch, port 3 might also be bad. I'd do the port switching dance first before buying a new NIC. FWIW, it's /extremely/ rare that a cable /goes/ bad. I've certainly created bad cables but nowadays, with a cable tester, no more. Swapping the cable of course is simple to do and probably will take less time than me writing this paragraph so it's worth the test. Cheers, -pablo -- openSUSE 12.1/KDE 4.x ISP: TekSavvy Bonded DSL; backhauled via a 6KM wireless link Assorted goodies: »pablo.blog.blueoakdb.com
	to forum · permalink · 2012-05-21 11:28:30 ·
timcuth Braves Fan Premium join:2000-09-18 Pelham, AL Reviews: ·AT&T Southeast	reply to timcuth Ok, I will try the router port switching suggestion, too. If I do decide I need a new NIC, this one appears to be a good fit for my needs: Intel PWLA8391GT. Any comments, pro or con? »www.newegg.com/Product/Product.a···33106121 Tim -- "Life is like this long line, except at the end there ain't no merry-go-round." - Arthur on The King of Queens ~ Project Hope ~
	to forum · permalink · 2012-05-21 11:42:46 ·
No_Strings Premium,Mod join:2001-11-22 The OC kudos:6 Host: Wireless Networking All Things Unix Cox HSI Efficient Southwest Chat	reply to timcuth said by timcuth: If I buy a new one, I will get an Intel Pro. Excellent choice. Best Linux support of any NIC chipset I've seen. Twice, I've had to bludgeon an onboard NIC into cooperating (one RealTek and one Marvell). Eventually, both issues were resolved with a new driver, but having the Intel card saved me troubleshooting time. -- If arrogant is the only word people use to describe me now, then I'd say I'm making progress. -- Colonel A.J. Bullard, Red Tails
	to forum · permalink · 2012-05-21 11:43:08 ·
markofmayhem Why not now? Premium join:2004-04-08 Pittsburgh, PA kudos:5	reply to timcuth What does: "lsmod \| grep r8" pull back in Ubuntu?
	to forum · permalink · 2012-05-21 13:08:46 ·
timcuth Braves Fan Premium join:2000-09-18 Pelham, AL Reviews: ·AT&T Southeast	said by markofmayhem: What does: "lsmod \| grep r8" pull back in Ubuntu? "r8168 240603 0" This is on 12.04, where I installed the driver downloaded from Realtek. Tim -- "Life is like this long line, except at the end there ain't no merry-go-round." - Arthur on The King of Queens ~ Project Hope ~
	to forum · permalink · 2012-05-21 14:23:59 ·
timcuth Braves Fan Premium join:2000-09-18 Pelham, AL Reviews: ·AT&T Southeast	reply to timcuth Here is a DSLReports speed test. This is on a 3mbps DSL service. Tim -- "Life is like this long line, except at the end there ain't no merry-go-round." - Arthur on The King of Queens ~ Project Hope ~
	to forum · permalink · 2012-05-21 14:34:33 ·
timcuth Braves Fan Premium join:2000-09-18 Pelham, AL Reviews: ·AT&T Southeast	reply to timcuth And here is the speed test with the ethernet disconnected, using the wireless connection. Tim -- "Life is like this long line, except at the end there ain't no merry-go-round." - Arthur on The King of Queens ~ Project Hope ~
	to forum · permalink · 2012-05-21 14:37:48 ·
pablo MVM join:2003-06-23 kudos:1	Try `ping'ing at the same time .... losing packets? -pablo
	to forum · permalink · 2012-05-21 14:39:38 ·
Xlogic Premium join:2002-10-17 Conyers, GA	reply to timcuth I don't know if this will help or not but when I had DSL I had to manually set the MTU to 1492 in network settings as even "automatic" will stay at 1500.
	to forum · permalink · 2012-05-21 17:04:50 ·
timcuth Braves Fan Premium join:2000-09-18 Pelham, AL Reviews: ·AT&T Southeast 1 edit	said by Xlogic: I don't know if this will help or not but when I had DSL I had to manually set the MTU to 1492 in network settings as even "automatic" will stay at 1500. Thanks for the advice, but that is not it. This system has been running without problems (and a fast ethernet connection) for almost a year. This problem just started a few days ago. No changes have been made to the network settings. Overtly, anyway. LATER - I tried it anyway, just to make sure. It did not help. Thanks, again. Tim -- "Life is like this long line, except at the end there ain't no merry-go-round." - Arthur on The King of Queens ~ Project Hope ~
	to forum · permalink · 2012-05-21 18:24:00 ·
Kearnstd Elf Wizard Premium join:2002-01-22 Mullica Hill, NJ	reply to No_Strings said by No_Strings: said by timcuth: If I buy a new one, I will get an Intel Pro. Excellent choice. Best Linux support of any NIC chipset I've seen. Twice, I've had to bludgeon an onboard NIC into cooperating (one RealTek and one Marvell). Eventually, both issues were resolved with a new driver, but having the Intel card saved me troubleshooting time. Intel NICs are great. They always just work and they work well. I am happy my Linux box has Intel Pro on board because I have no issues ever with network drivers. -- [65 Arcanist]Filan(High Elf) Zone: Broadband Reports
	to forum · permalink · 2012-05-21 19:16:33 ·
timcuth Braves Fan Premium join:2000-09-18 Pelham, AL Reviews: ·AT&T Southeast	reply to timcuth I am now beginning to back away from the hardware or cabling problem theory. Searches reveal many people all over everywhere having the exact same problem (ethernet remains connected, with periodic changes between full speed and drastic slowdowns). I can post some links if anyone is interested. I am almost tempted to install Windows just to see if it gets a stable connection. My suspicion is that it would.But no, I'm not going to go that far. Tim -- "Life is like this long line, except at the end there ain't no merry-go-round." - Arthur on The King of Queens ~ Project Hope ~
	to forum · permalink · 2012-05-22 09:34:16 ·
pablo MVM join:2003-06-23 kudos:1	Hi timcuth , I'm going to assume you didn't have a chance to run any tests last night? Cheers, -pablo
	to forum · permalink · 2012-05-22 09:45:27 ·

OS and Software > All Things Unix > [Solved] Wired connection trouble on Linux PC

Re: Wired connection trouble on Linux PC