5 Website Development Tips To Boost Your Business Growth Exponentially

 I have been receiving the following intermittent error over the last few weeks and it seems rebooting has been the quick fix.. 

it happened today, and now I will be monitoring this error more closely.  

If you are new and haven’t been following my other threads please read the below other wise you can skip:


Brief Exclamation  Squid is a proxy / reverse Proxy server ( Caches the web improving traffic)   and in my cast my ICAP is on the Proxy Server
ICAP is a program that site in-between to other programs (cause usually one isn’t designed to interact over the network)
In my case My Cache server is connecting to my anti-virus application Through Icap  (im am new with ICAP  but ill make my corrections as needed lol)


Squid = caching server ( saves all website by storing files which improving the speed of the internet and bandwidth for local users)
ICAP= An application that allows to programs to connect to each other that wasn’t designed to connect through the Application Layer..  (I am new to ICAP)
CLAIM = Linux Based Anti-virus
User goes to HTTP://www.cyfordtechnologies.com
Firewall first checks for viruses and (satisfying permission)  then sends the request to SQUID server,  (my network)
Squid checks for safe ports,  then connects to ICAP
ICAP send the request to the Anti-Virus
After Anti-virus checks the https://www.cyfordtechnologies.com file it send a response back  (Good or bad)  which i ICAP relays back to squid.
Squid Server Stores the File and Sends it to the user…



The Error______________________________________________________

The following error was encountered while trying to retrieve the URL: http://www.tagged.com/apps/pets.html?

    ICAP protocol error.

The system returned: [No Error]

This means that some aspect of the ICAP communication failed.

Some possible problems are:

    The ICAP server is not reachable.

    An Illegal response was received from the ICAP server.

Generated Thu, 02 Jan 2014 15:00:00 GMT by Cyford-Cache-99.corp.cyfordtechnologies.com (squid/

My server is was a single Virtual CPU ,  and I have squid running in multi thread  and 4 process / workers..

  1. My First thought is that ICAP is getting hammered. ( maybe icap which is connecting an anti-virus and the anti-virus is Queering every page the users  go to through 1000′ of virus definitions  with only 1 worker)Second Possibility is maybe ICAP is fine,  and the anti-virus server locked up ( Ill check next time this happens
    1. OK  I have shut the vm down and assigned it 4 CPU’s  hopefully the anti-virus and ICAP will use more threads.. after turning it back on it all works fine,  i will keep you updated here.



Another for sure  quick fix i found online – (  however i am attempting to fix the ICAP Issue without needing to modify squids time out period)

Squid has received at least one bad response from your ICAP server while it was down. As a result it has decided not to talk to your ICAP server for a period of time

If you want Squid to ignore outages on your ICAP server and always attempt a request you can set

icap_service_failure_limit -1

Setting this to -1 tells Squid to always connect to ICAP, setting a positive number indicates the number of failures allowed before Squid stops communicating with Squid. The period of time that Squid stops talking to ICAP is controlled by ‘icap_service_revival_delay’, it is a minimum of 30 seconds I think.



{jcomments on}

Published on: Mar 03, 2021

Categories: Web Development

    No Comments yet! Be the first one to write.

    Leave a Reply

    Your email address will not be published. Required fields are marked *