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-   -   Diagnosing network connections: Slow initial connection (http://www.linuxquestions.org/questions/linux-networking-3/diagnosing-network-connections-slow-initial-connection-798412/)

atp 03-28-2010 06:51 AM

Diagnosing network connections: Slow initial connection
 
Hi,

I want to identify why my ISP is sometimes slow, and wonder how and what tools to use.

The problem is as follows: While the lines are very fast, I experience that at times of day where there are presumably high traffic, a new initial connection is very slow and unstable.

For example getting response from DNS is slow. And after getting the answer, getting response from a web server is also slow. Or sometimes there is no response at all, and I have to retry.

Running a speed test will show high data rates. So it is only initial connection that is slow/unstable.

What is the explanation for these symptoms? Are there some tools and tests I can use to pinpoint the problem from home, without/before contacting the ISP?

troop 03-28-2010 07:16 AM

Code:

sudo ping -f -c 1000 ip_of_your_gateway
sudo ping -f -c 1000 ip_of_dns
sudo ping -f -c 1000 address_of_year_favorite_site

if packets loss in first case then contact the ISP.
if packets loss in second or third case then
Code:

sudo traceroute address

atp 03-28-2010 07:31 AM

Interesting, flood pinging my own wireless router, connected with a wire:
# ping -f -c 1000 192.168.1.1
PING 192.168.1.1 (192.168.1.1) 56(84) bytes of data.
.................................................................................................... .................................................................................................... .................................................................................................... .................................................................................................... .................................................................................................... ........
--- 192.168.1.1 ping statistics ---
1000 packets transmitted, 492 received, 50% packet loss, time 8207ms
rtt min/avg/max/mdev = 0.701/1.417/3.104/0.316 ms, ipg/ewma 8.215/0.921 ms

This seems very wrong?

atp 03-28-2010 07:55 AM

Had another router lying around. Same cables, same location:

ping -f -c 1000 192.168.1.254
PING 192.168.1.254 (192.168.1.254) 56(84) bytes of data.

--- 192.168.1.254 ping statistics ---
1000 packets transmitted, 1000 received, 0% packet loss, time 1026ms
rtt min/avg/max/mdev = 0.941/0.980/2.092/0.102 ms, ipg/ewma 1.027/0.964 ms

troop 03-28-2010 10:26 PM

Quote:

50% packet loss, time 8207ms
This seems very wrong?
Yes, it's very wrong.
Quote:

0% packet loss, time 1026ms
It's good. I have same on my wireless router.


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