Why Very Slow DNS on 8.2, But Not on WinXP?
Anyone know why name resolution using my cable provider's nameservers is impossibly slow on a standard untweaked 8.2 install, but quite fast with WinXP on the same machine, same provider, same nameservers? I see the same slowness whether or not my firewall is running, and whether or not I'm running a local cacheing nameserver. Thanks.
Not sure if this is the same but here is my post to this list of 3 weeks ago I have just upgraded suse8.1 to 8.2. One effect was to give me very slow browsing, looking like slow dns lookup. That is downloads were full speed (60k ish) once they were started, but changing to a new page could give a 20sec pause. After some googling I found I needed to "turn off ip6" by changing which of these lines was commented in etc/modules.conf #alias net-pf-10 ipv6 alias net-pf-10 off This worked and I am now back to normal. Can anyone tell me what this line does, and exactly what I have turned off? (or which manual I should read) Thanks David On Friday 26 September 2003 2:58 pm, wgerrard wrote:
Anyone know why name resolution using my cable provider's nameservers is impossibly slow on a standard untweaked 8.2 install, but quite fast with WinXP on the same machine, same provider, same nameservers?
I see the same slowness whether or not my firewall is running, and whether or not I'm running a local cacheing nameserver.
Thanks.
david stevenson wrote:
After some googling I found I needed to "turn off ip6" by changing which of these lines was commented in etc/modules.conf
#alias net-pf-10 ipv6 alias net-pf-10 off
Found that by Googling, too, but it didn't work here. I also did a quick install of Slackware 9 and saw the same thing happening. Very strange.
wgerrard wrote:
Anyone know why name resolution using my cable provider's nameservers is impossibly slow on a standard untweaked 8.2 install, but quite fast with WinXP on the same machine, same provider, same nameservers?
I see the same slowness whether or not my firewall is running, and whether or not I'm running a local cacheing nameserver.
Thanks.
I'd like to understand this a bit more before I bite. Please describe "impossibly slow". What application are you running that demonstrates the slowness? Can you quantify a bit more? What hardware is between the actual cable and your computer? Software-wise I created an /etc/resolv.conf file with three lines and that was it and mozilla is fast enough.
expatriate wrote:
Please describe "impossibly slow". What application are you running that demonstrates the slowness? Can you quantify a bit more?
Fair enough. "Impossibly slow" means too slow to comfortably use the net. I switched this week from a DSL provider to a cable provider -- Time Warner Roadrunner. The slow DNS was apparent as soons as I began using RoadRunner. This is a simple hardware setup: one PC (2700 Athlon XP) and one cable "modem" (Motorola SB5100). Browsing with Mozilla/Konqueror/Epiphany/Galeon: Lookup of new URLs takes 15-30 seconds; once the lookup is done, pages load fast; Pinging common sites (Yahoo, Mozilla, etc.) shows same symptoms: 15-30 seconds to resolve the name. Anything that doesn't require name resolution, e.g., browsing to an IP address, isn't delayed. I see the same behavior with Slackware. I did a clean install of WinXP -- same machine, same provider, same nameservers -- and see none of this slowness.
wgerrard wrote:
expatriate wrote:
Please describe "impossibly slow". What application are you running that demonstrates the slowness? Can you quantify a bit more?
Fair enough. "Impossibly slow" means too slow to comfortably use the net.
I switched this week from a DSL provider to a cable provider -- Time Warner Roadrunner. The slow DNS was apparent as soons as I began using RoadRunner.
This is a simple hardware setup: one PC (2700 Athlon XP) and one cable "modem" (Motorola SB5100).
Browsing with Mozilla/Konqueror/Epiphany/Galeon: Lookup of new URLs takes 15-30 seconds; once the lookup is done, pages load fast;
Pinging common sites (Yahoo, Mozilla, etc.) shows same symptoms: 15-30 seconds to resolve the name.
Anything that doesn't require name resolution, e.g., browsing to an IP address, isn't delayed.
I see the same behavior with Slackware. I did a clean install of WinXP -- same machine, same provider, same nameservers -- and see none of this slowness.
OK, I'm not an expert on this but can you answer the following:
1) Are you using the ethernet connection? 2) If it is, are you using a static IP address or some internal DHCP? (I only use ethernet since I have a switch between my modem and the house computers) 3) What does ipconfig say? (run as root) 3) Can you show us your /etc/resolv.conf file? Does it contain more than TWR's nameservers?
expatriate wrote:
1) Are you using the ethernet connection? 2) If it is, are you using a static IP address or some internal DHCP? (I only use ethernet since I have a switch between my modem and the house computers) 3) What does ipconfig say? (run as root) 3) Can you show us your /etc/resolv.conf file? Does it contain more than TWR's nameservers?
--Ethernet, a RealTek card; --DHCP from RoadRunner; --no switches, hubs, routers, etc.; --can't show you ipconfig output since I've got XP on the machine right now (it did show the card took the leased IP address and seemed normal otherwise; I do recall MTU was 1500) --ditto for /etc/resolv.conf, but it was OK: three RoadRunner nameservers and their search domain. Thanks.
* wgerrard (wgerrard@nc.rr.com) [030926 09:52]:
expatriate wrote:
1) Are you using the ethernet connection? 2) If it is, are you using a static IP address or some internal DHCP? (I only use ethernet since I have a switch between my modem and the house computers) 3) What does ipconfig say? (run as root) 3) Can you show us your /etc/resolv.conf file? Does it contain more than TWR's nameservers?
--Ethernet, a RealTek card; --DHCP from RoadRunner; --no switches, hubs, routers, etc.; --can't show you ipconfig output since I've got XP on the machine right now (it did show the card took the leased IP address and seemed normal otherwise; I do recall MTU was 1500) --ditto for /etc/resolv.conf, but it was OK: three RoadRunner nameservers and their search domain.
Was it slow on your DSL setup? If it wasn't then it may be the fact that their DNS servers are just overloaded and slow to respond. I've seen this quite a lot with different providers. I also saw it with my company since we are a telco/ISP. We had our DNS servers on some slow machines 4x450 E420's (2 machines) and they were ok..but a bit slow. But then myself and a co-worker rebuilt the machines using Sunfire v210's and things zoom along now. It may not be anything you did ..that is if your DSL wasn't slow but the cable is. Also, remember that one of the drawbacks of cable is that you're on a grid with other users. I don't know that cable has overcome the problem of " the more users on the grid, the slower the connection " which cable use to suffer from. Since your on XP try doing some traceroutes and what not to see if there is packet loss and what your response times are. -- Ben Rosenberg ---===---===---===--- mailto:ben@whack.org ----- If two men agree on everything, you can be sure that only one of them is doing the thinking.
Ben Rosenberg wrote:
Was it slow on your DSL setup? If it wasn't then it may be the fact that their DNS servers are just overloaded and slow to respond.
Nope, DSL was fine. With cable, traceroutes, etc., on Windows are good, showing no packet loss, etc. But, there was also no packet loss with SuSe and Slackware, just very slow name resolution. Example: one of RoadRunners name servers is 5 hops and about 20 miles from me. A traceroute to it took 3-5 minutes; in Windows, it takes 3-5 seconds. I'd be inclined to attribute this to sluggish or overworked RoadRunner nameservers, but there is no evidence of that using XP. In my neighborhood, their busiest time is between 5 and 9 pm, when everyone is home from work and the kids are online. I only notice a marginal slowdown in Windows, but using the net on SuSe/Slackware became unusable during that time.
Uninstall bind from Yast. On Friday 26 September 2003 12:33 pm, wgerrard wrote:
Ben Rosenberg wrote:
Was it slow on your DSL setup? If it wasn't then it may be the fact that their DNS servers are just overloaded and slow to respond.
Nope, DSL was fine.
With cable, traceroutes, etc., on Windows are good, showing no packet loss, etc. But, there was also no packet loss with SuSe and Slackware, just very slow name resolution. Example: one of RoadRunners name servers is 5 hops and about 20 miles from me. A traceroute to it took 3-5 minutes; in Windows, it takes 3-5 seconds.
I'd be inclined to attribute this to sluggish or overworked RoadRunner nameservers, but there is no evidence of that using XP. In my neighborhood, their busiest time is between 5 and 9 pm, when everyone is home from work and the kids are online. I only notice a marginal slowdown in Windows, but using the net on SuSe/Slackware became unusable during that time.
-- --------------------------------------------------- Dave Grosvold Cell: (479) 651-3441 dave@rcanyon.com ---------------------------------------------------
I've seen this when no gateway IP address was set up in YaST. I have two nets at home, one for business use and one for home use. Each net has a separate drop from Time Warner Cable, with the business net having fixed IP address service. For the home net, I use a D-Link wireless router/switch/firewall (about $75). The D-Link box gets the IP from the cable company, and then I set the gateway on the home net Linux box to 192.168.0.1 (this is the default private network address on the LAN side of the D-Link box; I've changed it to something else...) On the business net, the gateway IP address is fixed, and is of course provided by the cable company. Bottom Line, get a D-Link or LinkSys cable modem/router/switch and I'll wager that your problem will disappear. Good luck! L. Mark Stone President Reliable Networks of Maine, LLC 477 Congress Street, 5th Floor Portland, ME 04107 Tel: (207) 772-5678 Cell: (917) 597-2057 Email: LMStone@RNoME.com mailto:LMStone@RNoME.com Web: http://www.RNoME.com http://www.RNoME.com/ |-----Original Message----- |From: wgerrard [mailto:wgerrard@nc.rr.com] |Sent: Friday, September 26, 2003 9:58 AM |To: suse-linux-e@suse.com |Subject: [SLE] Why Very Slow DNS on 8.2, But Not on WinXP? | | |Anyone know why name resolution using my cable provider's |nameservers is |impossibly slow on a standard untweaked 8.2 install, but quite |fast with |WinXP on the same machine, same provider, same nameservers? | |I see the same slowness whether or not my firewall is running, and |whether or not I'm running a local cacheing nameserver. | |Thanks. | | | | | |-- |Check the headers for your unsubscription address |For additional commands send e-mail to |suse-linux-e-help@suse.com Also check the archives at http://lists.suse.com Please read the FAQs: suse-linux-e-faq@suse.com
participants (6)
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Ben Rosenberg -
David C. Grosvold -
david stevenson -
expatriate -
L. Mark Stone -
wgerrard