Does Apache webserver process http pipelined requests in parallel

apache-2.2httppipelining

Given we have Apache web server and a client which sends several pipelined requests.

According to RFC server is supposed to return responses in the same order as requests are sent. So, does it mean server processes requests sequentially or it would still process them in parallel only waiting for slow ones when outputting the lot?

If they are processed in parallel then faster requests (in terms of amount of server time required) which were sent later will be finished earlier then slow requests.

Eg.
Request 1 requires 60 seconds to be processed
Request 2 – 5 sec
Request 3 – 5 sec
Request 4 – 30 sec
Request 5 – 5 sec

All these 5 requests are sent one after another. Will requests 2,3,5 be completely processed (but not returned) before slow requests 1 and 5 or server would wait for each requests before starting processing another one?

Best Answer

After making several tests i can confirm that Apache does infact wait for each request to be processed before starting processing the next one so processing is SEQUENTIAL.

Related Solutions

DoS – Apache threads hanging when not receiving TCP ACKs after sending HTTP response

put a litespeed infront of apache. That can solve your problem. That is exactly what we do for slow request, reflection and regular ddos problems. Solve means at least at some scale i meant.

Edited Section:

Sure,

Litespeed is a web server/load balancer a type of reverse proxy also rate base limiting aviable ddos attack mitigation software. We had the same type of attacks you meantioned and much more worse close to 400.000 http request per second based attacks. We install a litespeed server with 24 core 128 gb ram litespeeds runs in mounted ram and operation system runs in raid0 striped ssd disks. And that solved and stop this attack.

Also via configuration and setup you can stop the slow loris attack. We still have a load balancer, but the incoming traffic passes through first the litespeed then proxeyed to our hw loadbalancer.

Apache mod_substitute on HTTP requests to reverse-proxied host

Why not do the following: Define two DNS names for your external printer, eg.

printer-1-external.mydomain.com CNAME external-server.mydomain.com
printer-2-external.mydomain.com CNAME external-server.mydomain.com

You could even use the same names as you use internally. Have the internal DNS resolve printer names directly to the printer, and the external DNS to your external IP...

Add two name based virtual hosts on your server:

<VirtualHost *:80>
    ServerName printer-1-external.mydomain.com
    ProxyPass / http://printer-1-local-ip/
</VirtualHost>
<VirtualHost *:80>
    ServerName printer-2-external.mydomain.com
    ProxyPass / http://printer-2-local-ip/
</VirtualHost>

That way your IPP request for http://printer-2-external.mydomain.com/printer will have the correct service name in its post parameters.

Best Answer

Related Solutions

DoS – Apache threads hanging when not receiving TCP ACKs after sending HTTP response

Apache mod_substitute on HTTP requests to reverse-proxied host

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