httpd-users mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From fchan <fc...@molsci.org>
Subject Re: [users@httpd] Responding to ping
Date Wed, 17 Sep 2008 21:37:37 GMT
Dragon is correct. Apache can be overload due many issues (ie overly 
popular site or DoS attack, etc.) but the system will still ping and 
respond to other ports and services. Apache will hit the limit and 
not respond to http request, which is good, to prevent your system 
from DoS or crash.
There are some firewalls that can detect and thwart some  DoS attacks 
which you can research on your own for if you wish.

Frank

>Arnab Ganguly did speak thusly:
>>Hi All,
>>Is it possible that Apache server stops responding under heavy 
>>load, but it responds to ping? What would be the possible causes 
>>for this?
>>Remote client is getting connection refused when it tries to 
>>connect.But when the I ping the server from the client box it shows 
>>the server is alive.
>>Thanks
>>-A
>---------------- End original message. ---------------------
>
>Yes, a machine can indeed respond to a ping (ICMP echo request) 
>while another application is not responding.
>
>Apache can get completely bogged down by a large number of requests 
>but the ICMP mechanism is built into the TCP/IP stack in the OS and 
>takes very little in the way of processor or time resources to 
>implement. As far as I know, all modern OS platforms on which Apache 
>runs are multitasking with a preemptive scheduler which means each 
>application gets some share of the processor time on a periodic 
>basis. So it is entirely possible that it will continue to work 
>while Apache is overloaded.
>
>Dragon
>
>~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>  Venimus, Saltavimus, Bibimus (et naribus canium capti sumus)
>~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
>
>---------------------------------------------------------------------
>The official User-To-User support forum of the Apache HTTP Server Project.
>See <URL:http://httpd.apache.org/userslist.html> for more info.
>To unsubscribe, e-mail: users-unsubscribe@httpd.apache.org
>   "   from the digest: users-digest-unsubscribe@httpd.apache.org
>For additional commands, e-mail: users-help@httpd.apache.org


---------------------------------------------------------------------
The official User-To-User support forum of the Apache HTTP Server Project.
See <URL:http://httpd.apache.org/userslist.html> for more info.
To unsubscribe, e-mail: users-unsubscribe@httpd.apache.org
   "   from the digest: users-digest-unsubscribe@httpd.apache.org
For additional commands, e-mail: users-help@httpd.apache.org


Mime
View raw message