How to debug "HTTP request sent, awaiting response"?

by Sandra   Last Updated February 22, 2017 12:00 PM

I have a Linux server on an ADSL connection, and I just noticed that sometimes I get

Connecting to example.com|xxx.xxx.xxx.122|:80... connected.
HTTP request sent, awaiting response...

when I use wget or e.g. a browser like firefox.

In the case of wget pressing CTRL-C and then try again "solves the problem", and in the case of firefox, reloading the page also makes the page load.

It seams to be random when it happens. I have tried to change the DNS to Google's DNS, but I still get the same problems there.

Question

How do I debug something like that, so I can find the source of the problem or perhaps a pattern?



Answers 3


Have you ever tried waiting to see what HTTP status code returns?

To debug this case, open 2 terminals: in the first, ssh to your server and type:

# tcpdump -vv -s0 tcp port 80 -w /tmp/example.pcap

(you can also append and src host <client_IP> to filter junk requests)

and in the second, use wget to browse your website, reproduce this problem and switch to the first terminal and press Ctrl+C.

Copy this .pcap file to the client and open with Wireshark to see what happens.

quanta
quanta
September 24, 2011 15:29 PM

If you see:

HTTP request sent, awaiting response...

This means that the DNS works fine, that the TCP connection is in established state and the request was send. I think that the cause of your problems is the remote server that might be busy.

As @quanta said a network capture will give you better details. In Wireshark just use Follow TCP Stream to see the HTTP conversation. Pay attention to ICMP messages too.

Mircea Vutcovici
Mircea Vutcovici
September 24, 2011 15:36 PM

Restart your Apache Server. This should solve the problem.

Abhishek Goel
Abhishek Goel
February 22, 2017 11:59 AM

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