Re: Only some websites will open - Ubuntu

The Natural Philosopher wrote:
kubismo@xxxxxxxxx wrote:
On Jun 7, 7:48 pm, The Natural Philosopher <a...@xxx> wrote:

> go on at the moment.
Well you got me thinking, and I found this page.

http://dsd.lbl.gov/TCP-tuning/linux.html

Thanks for your response.

And thanks for that link. First of all because it's another site that
I can actually bring up on this computer. Am I see a pattern here? The
three sites that I can see so far are all sites that one would expect
to have some advanced knowledge of how the Internet works (google,
mozilla and this TCP tuning site). Coincidence?

Ok..one thing I found by looking at that page is that you should use
"netstat -s" to assess whether there are a high level of retransmits
going on.

Here's what I get with netstat -s


Ip:
8310 total packets received
0 forwarded
0 incoming packets discarded
3730 incoming packets delivered
4201 requests sent out
Icmp:
74 ICMP messages received
0 input ICMP message failed.
ICMP input histogram:
destination unreachable: 4
echo replies: 70
4 ICMP messages sent
0 ICMP messages failed
ICMP output histogram:
destination unreachable: 4
Tcp:
236 active connections openings
0 passive connection openings
0 failed connection attempts
2 connection resets received
6 connections established
3409 segments received
3442 segments send out
410 segments retransmited

That seems high to me.. for 3400 segments 400 retransmitted..my stats
show 30,000 in about 12 million..which would would equate to 7-8 only
for your traffic volume.

I get this with Verizon FiOS Internet connection using Red Hat Enterprise
Linux 3.
Tcp:
62454 active connections openings
850 passive connection openings
0 failed connection attempts
1386 connection resets received
3 connections established
7065987 segments received
6872051 segments send out
3094 segments retransmited
3 bad segments received.
23711 resets sent

0 bad segments received.
45 resets sent
Udp:
216 packets received
4 packets to unknown port received.
0 packet receive errors
218 packets sent
UdpLite:
TcpExt:
48 TCP sockets finished time wait in fast timer
184 delayed acks sent
Quick ack mode was activated 21 times
1647 packet headers predicted
534 acknowledgments not containing data received
268 predicted acknowledgments
7 congestion windows recovered after partial ack
0 TCP data loss events
2 timeouts after SACK recovery
1 timeouts in loss state
67 other TCP timeouts
10 DSACKs sent for old packets
1 DSACKs received
6 connections reset due to unexpected data
2 connections reset due to early user close
29 connections aborted due to timeout

That's high too..

I get this:

TcpExt:
6 packets pruned from receive queue because of socket buffer overrun
ArpFilter: 0
6013 TCP sockets finished time wait in fast timer
1 time wait sockets recycled by time stamp
3 packets rejects in established connections because of timestamp
662448 delayed acks sent
22 delayed acks further delayed because of locked socket
Quick ack mode was activated 2901 times
1977127 packets directly queued to recvmsg prequeue.
1264793 packets directly received from backlog
542973932 packets directly received from prequeue
1823295 packets header predicted
1968417 packets header predicted and directly queued to user
TCPPureAcks: 79918
TCPHPAcks: 3527750
TCPRenoRecovery: 0
TCPSackRecovery: 25
TCPSACKReneging: 0
TCPFACKReorder: 0
TCPSACKReorder: 0
TCPRenoReorder: 0
TCPTSReorder: 0
TCPFullUndo: 0
TCPPartialUndo: 0
TCPDSACKUndo: 0
TCPLossUndo: 170
TCPLoss: 17
TCPLostRetransmit: 1
TCPRenoFailures: 5
TCPSackFailures: 15
TCPLossFailures: 12
TCPFastRetrans: 63
TCPForwardRetrans: 2
TCPSlowStartRetrans: 18
TCPTimeouts: 715
TCPRenoRecoveryFail: 0
TCPSackRecoveryFail: 1
TCPSchedulerFailed: 3
TCPRcvCollapsed: 255
TCPDSACKOldSent: 1725
TCPDSACKOfoSent: 49
TCPDSACKRecv: 29
TCPDSACKOfoRecv: 0
TCPAbortOnSyn: 0
TCPAbortOnData: 1262
TCPAbortOnClose: 621
TCPAbortOnMemory: 0
TCPAbortOnTimeout: 265
TCPAbortOnLinger: 0
TCPAbortFailed: 0
TCPMemoryPressures: 0


Another thing occurs to me.. is FTP working ok to large FTP sites?

Not through the browser anyway. I don't know how to use FTP through
the console.


"ftp <sitename>"

Then log in and do a get or a put

I can ping a number of websites (but not many others).

My neighbor (who works with this stuff) looked at my network traffic
and said the acks seemed to be getting through. He also pointed out
something a bit weird - I'm
not sure if it's related to my present problem - but my computer kept
trying to access a ubuntu update mirror (one that's not in my
sources.list).



Well its fairly clear that somehow you are losing packets - a lot of
packets. The question is why...


--
.~. Jean-David Beyer Registered Linux User 85642.
/V\ PGP-Key: 9A2FC99A Registered Machine 241939.
/( )\ Shrewsbury, New Jersey http://counter.li.org
^^-^^ 07:35:01 up 21 days, 22:20, 3 users, load average: 4.25, 4.20, 4.08
.

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