Cable connection crawls and IPV6 is not the culprit

bmccorm2 · 01-22-2007, 11:00 PM

I recently switched to Ubuntu and am very happy except for one small quibble. I have a cable connection via a wireless adapter. Everything works fine, except the speed is unbearably slow! It is strange because downloading large files it is fine. When I go to a bandwidth tester it is also fine (about 2000 K/b). However, when I go to any website, it seems like it takes about 10 seconds to catch, and then it downloads the site (google for example takes about 13 seconds to load). I have IPV6 disabled system wide (in /etc/network) and it happens on whatever browser I use (opera, firefox, etc).

I am fairly positive it is my Linux settings because I dual boot with Win XP and the connection is fine. However, I go to a different location and plug in, and the connection is fine. I have tried everything from reinstalling the OS to resetting the router and the modem to no avail. Any help would be gladly appreciated!

Thanks!

acid_kewpie · 01-23-2007, 03:53 PM

sounds like DNS to me. run tcpdump and see what's actaully going back and forth before things finally kick in, i'd speciulate you'll see a lot of unanswred dns requests going off to a dodgy / nonexistant server, just a hunch... one that i was subject myself to this mornign actually.

bmccorm2 · 01-23-2007, 10:22 PM

Thanks for the reply. I ran tcpdump and it gave the following output (when going to google.com):

Code:

bryan@bryan-laptop:~$ sudo tcpdump
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on wlan0, link-type EN10MB (Ethernet), capture size 96 bytes
21:14:32.261813 IP 192.168.10.136.32826 > cns.beaverton.or.bverton.comcast.net.domain:  5434+ A? www.google.com. (32)
21:14:32.262606 IP 192.168.10.136.32827 > cns.cmc.co.denver.comcast.net.domain:  14013+ PTR? 146.69.87.68.in-addr.arpa. (43)
21:14:32.316626 IP cns.beaverton.or.bverton.comcast.net.domain > 192.168.10.136.32826:  5434 4/0/0 CNAME www.l.google.com.,[|domain]
21:14:35.632980 IP 192.168.10.136.32828 > cns.beaverton.or.bverton.comcast.net.domain:  24681+ AAAA? google.com. (28)
21:14:35.695052 IP cns.beaverton.or.bverton.comcast.net.domain > 192.168.10.136.32828:  24681 0/1/0 (78)
21:14:35.695176 IP 192.168.10.136.32828 > cns.cmc.co.denver.comcast.net.domain:  63907+ AAAA? google.com.hsd1.co.comcast.net. (48)
21:14:37.264516 IP 192.168.10.136.32829 > cns.beaverton.or.bverton.comcast.net.domain:  14013+ PTR? 146.69.87.68.in-addr.arpa. (43)
21:14:37.318148 IP cns.beaverton.or.bverton.comcast.net.domain > 192.168.10.136.32829:  14013 1/0/0 (93)
21:14:37.318498 IP 192.168.10.136.32829 > cns.cmc.co.denver.comcast.net.domain:  64635+ PTR? 136.10.168.192.in-addr.arpa. (45)
21:14:40.700647 IP 192.168.10.136.32830 > cns.beaverton.or.bverton.comcast.net.domain:  63907+ AAAA? google.com.hsd1.co.comcast.net. (48)
21:14:40.764233 IP cns.beaverton.or.bverton.comcast.net.domain > 192.168.10.136.32830:  63907 NXDomain 0/1/0 (128)
21:14:40.764757 IP 192.168.10.136.32830 > cns.cmc.co.denver.comcast.net.domain:  3545+ A? google.com. (28)
21:14:42.324170 IP 192.168.10.136.32831 > cns.beaverton.or.bverton.comcast.net.domain:  64635+ PTR? 136.10.168.192.in-addr.arpa. (45)
21:14:42.375044 IP cns.beaverton.or.bverton.comcast.net.domain > 192.168.10.136.32831:  64635 NXDomain 0/0/0 (45)
21:14:42.375601 IP 192.168.10.136.32831 > cns.cmc.co.denver.comcast.net.domain:  19445+ PTR? 98.85.87.68.in-addr.arpa. (42)
21:14:45.767325 IP 192.168.10.136.32832 > cns.beaverton.or.bverton.comcast.net.domain:  3545+ A? google.com. (28)
21:14:45.822450 IP cns.beaverton.or.bverton.comcast.net.domain > 192.168.10.136.32832:  3545 3/0/0 A eh-in-f99.google.com,[|domain]
21:14:45.822878 IP 192.168.10.136.53285 > eh-in-f99.google.com.www: S 2314452697:2314452697(0) win 5840 <mss 1460,sackOK,timestamp 49588 0,nop,wscale 2>
21:14:45.921223 IP eh-in-f99.google.com.www > 192.168.10.136.53285: S 1257097045:1257097045(0) ack 2314452698 win 8190 <mss 1460>
21:14:45.921282 IP 192.168.10.136.53285 > eh-in-f99.google.com.www: . ack 1 win 5840
21:14:45.921626 IP 192.168.10.136.53285 > eh-in-f99.google.com.www: P 1:705(704) ack 1 win 5840
21:14:46.023217 IP eh-in-f99.google.com.www > 192.168.10.136.53285: . ack 705 win 6588
21:14:46.032043 IP eh-in-f99.google.com.www > 192.168.10.136.53285: P 1:425(424) ack 705 win 6588
21:14:46.032068 IP 192.168.10.136.53285 > eh-in-f99.google.com.www: . ack 425 win 6432
21:14:46.033623 IP 192.168.10.136.32832 > cns.cmc.co.denver.comcast.net.domain:  19338+ AAAA? www.google.com. (32)
21:14:47.375019 IP 192.168.10.136.32833 > cns.beaverton.or.bverton.comcast.net.domain:  19445+ PTR? 98.85.87.68.in-addr.arpa. (42)
21:14:47.426609 IP cns.beaverton.or.bverton.comcast.net.domain > 192.168.10.136.32833:  19445 1/0/0 PTR[|domain]
21:14:47.428120 IP 192.168.10.136.32833 > cns.cmc.co.denver.comcast.net.domain:  38071+ PTR? 99.207.14.72.in-addr.arpa. (43)
21:14:51.034045 IP 192.168.10.136.32834 > cns.beaverton.or.bverton.comcast.net.domain:  19338+ AAAA? www.google.com. (32)
21:14:51.095501 IP cns.beaverton.or.bverton.comcast.net.domain > 192.168.10.136.32834:  19338 1/1/0 CNAME www.l.google.com. (100)
21:14:51.095770 IP 192.168.10.136.32834 > cns.cmc.co.denver.comcast.net.domain:  9100+ A? www.google.com. (32)
21:14:52.429706 IP 192.168.10.136.32835 > cns.beaverton.or.bverton.comcast.net.domain:  38071+ PTR? 99.207.14.72.in-addr.arpa. (43)
21:14:52.490182 IP cns.beaverton.or.bverton.comcast.net.domain > 192.168.10.136.32835:  38071 1/0/0 (77)
21:14:56.101618 IP 192.168.10.136.32835 > cns.beaverton.or.bverton.comcast.net.domain:  9100+ A? www.google.com. (32)
21:14:56.156189 IP cns.beaverton.or.bverton.comcast.net.domain > 192.168.10.136.32835:  9100 4/0/0 CNAME www.l.google.com.,[|domain]
21:14:56.156729 IP 192.168.10.136.50780 > po-in-f104.google.com.www: S 2336237910:2336237910(0) win 5840 <mss 1460,sackOK,timestamp 52171 0,nop,wscale 2>
21:14:56.157057 IP 192.168.10.136.32835 > cns.cmc.co.denver.comcast.net.domain:  11805+ PTR? 104.253.14.72.in-addr.arpa. (44)
21:14:56.221403 IP po-in-f104.google.com.www > 192.168.10.136.50780: S 4230956144:4230956144(0) ack 2336237911 win 8190 <mss 1460>
21:14:56.221456 IP 192.168.10.136.50780 > po-in-f104.google.com.www: . ack 1 win 5840
21:14:56.221848 IP 192.168.10.136.50780 > po-in-f104.google.com.www: P 1:666(665) ack 1 win 5840
21:14:56.290449 IP po-in-f104.google.com.www > 192.168.10.136.50780: . ack 666 win 6930
21:14:56.297232 IP po-in-f104.google.com.www > 192.168.10.136.50780: . 1:1431(1430) ack 666 win 6930
21:14:56.297256 IP 192.168.10.136.50780 > po-in-f104.google.com.www: . ack 1431 win 8580
21:14:56.297721 IP po-in-f104.google.com.www > 192.168.10.136.50780: P 1431:2204(773) ack 666 win 6930
21:14:56.297746 IP 192.168.10.136.50780 > po-in-f104.google.com.www: . ack 2204 win 11440
21:14:56.328220 IP po-in-f104.google.com.www > 192.168.10.136.50780: . 1:1431(1430) ack 666 win 6930
21:14:56.328266 IP 192.168.10.136.50780 > po-in-f104.google.com.www: . ack 2204 win 11440
21:14:56.403284 IP 192.168.10.136.50781 > po-in-f104.google.com.www: S 2329540237:2329540237(0) win 5840 <mss 1460,sackOK,timestamp 52234 0,nop,wscale 2>
21:14:56.469767 IP po-in-f104.google.com.www > 192.168.10.136.50781: S 3619770:3619770(0) ack 2329540238 win 8190 <mss 1460>
21:14:56.469814 IP 192.168.10.136.50781 > po-in-f104.google.com.www: . ack 1 win 5840
21:14:56.470097 IP 192.168.10.136.50781 > po-in-f104.google.com.www: P 1:828(827) ack 1 win 5840
21:14:56.539233 IP po-in-f104.google.com.www > 192.168.10.136.50781: . ack 828 win 6840
21:14:56.542223 IP po-in-f104.google.com.www > 192.168.10.136.50781: P 1:128(127) ack 828 win 6840
21:14:56.542247 IP 192.168.10.136.50781 > po-in-f104.google.com.www: . ack 128 win 5840
21:14:56.705267 IP 192.168.10.136.50780 > po-in-f104.google.com.www: P 666:1485(819) ack 2204 win 11440
21:14:56.775572 IP po-in-f104.google.com.www > 192.168.10.136.50780: P 2204:2331(127) ack 1485 win 8470
21:14:56.775617 IP 192.168.10.136.50780 > po-in-f104.google.com.www: . ack 2331 win 11440
21:15:01.158951 IP 192.168.10.136.32836 > cns.beaverton.or.bverton.comcast.net.domain:  11805+ PTR? 104.253.14.72.in-addr.arpa. (44)
21:15:01.214634 IP cns.beaverton.or.bverton.comcast.net.domain > 192.168.10.136.32836:  11805 1/0/0 (79)
21:15:06.207647 arp who-has 192.168.10.136 tell 192.168.10.1
21:15:06.207678 arp reply 192.168.10.136 is-at 00:0f:b5:8a:ac:d2 (oui Unknown)
21:15:06.207969 IP 192.168.10.136.32836 > cns.cmc.co.denver.comcast.net.domain:  15279+ PTR? 1.10.168.192.in-addr.arpa. (43)
21:15:08.153905 arp who-has 192.168.10.3 tell 192.168.10.1

63 packets captured
139 packets received by filter
0 packets dropped by kernel

I have no clue what any of this means. I should say that I recently tried to give my computer a static IP address (for port forwarding purposes) and I am fairly sure that I have those settings correct, otherwise I would not be able to access the net, right? Anyway, I put all the settings back to DHCP and everything is still the same. Thanks again for any help.

acid_kewpie · 01-24-2007, 02:03 AM

no, no one ever does seem to undersatnd it... never sure why...

Essentailly you can see that for the first 12 seconds of the capture, there is nothign but dns related traffic. your isp is not telling you where google is, until it finally tells you to connect to eh-in-f99.google.com. first off you ask for www.google.com which your isp says is another name for www.l.google.com (which it is). then you ask for an AAAA record (meaning any info) about google.com which i don't really understand the point of, but essentially doesn't give you a valid IP address. from then on you can see your systems clutching at straws, tagging parts of your isp's domain name on in case google.com is just an abbreviation... and finally you get a response when you ask for the normal A record for google.com.

basically, try adding another name server, or using a different one. should fix things up i'd imagine.

bmccorm2 · 01-24-2007, 09:58 AM

Wow thank you. I replaced the primary DNS with the secondary DNS that my ISP provided and everything is back to normal. I can't thank you enough