Re: [squid-users] How to fix a "Zero Sized Reply" error

Hey Bastien,

I have seen this problem couple times being caused by wrong MTU used by
some points in the network Infrastructure,

Try to make sure another application other then squid has a success
while fetching the url.
try to find out the path MTU.

if you are not sure about it you can try the manual way by using ping
with a specific size and calculate manually the PMTU to a specific node\IP.

I had a small script which was pretty nice to do the trick couple times at:
http://rcl-rs-vvg.blogspot.co.il/2011/09/discovering-largest-supported-mtu.html

and nmap also has a nice script for that:
nmap --script path-mtu www.example.com

By the way what OS are you using squid on?

Regards,
Eliezer

On 1/17/2013 8:47 AM, Amos Jeffries wrote:
> On 17/01/2013 5:35 a.m., Bastien Ceriani wrote:
>> Hi,
>>
>> We use Squid 3.1.20.
>
> Firstly please upgrade this Squid if possible. 3.1 series is outdated
> and up to a .23 release now anyway due to security bugs. Current Squid
> release is 3.2.6.
>
>
>> We are often exposed to a problem which return a "Zero Sized Error".
>>
>> Can i fix it with some options on the squid configuration file ?
>
> It depends on why "the server is not sending any information back to
> Squid". If you can determine what type of HTTP requests *do* get a
> response from this server and how they differ from what is being relayed
> by your Squid you have a chance at discovering what settings might make
> it work.
>
>
>> I tried all of things mentioned after :
>>
>> - Delete or rename your cookie file and configure your browser to
>> prompt you before accepting any new cookies.
>> - Disable HTTP persistent connections with the
>> server_persistent_connections and client_persistent_connections
>> directives.
>> - Disable any advanced TCP features on the Squid system. Disable ECN
>> on Linux with echo 0 > /proc/sys/net/ipv4/tcp_ecn/.
>>
>> I will try to find the origin of the problem with a tcpdump on my
>> proxy my i don't known how could i exploit it.
>> This is the result of the TCP stream between my proxy and the website :
>>
>> GET / HTTP/1.1
>> Host: www.mopub.com
>> User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:17.0) Gecko/20100101
>> Firefox/17.0
>> Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
>> Accept-Language: en-US,en;q=0.5
>> Accept-Encoding: gzip, deflate
>> Via: 1.1 localhost (squid/3.1.20)
>> X-Forwarded-For: 192.168.1.137
>> Cache-Control: max-age=259200
>> Connection: keep-alive
>
> As you can see. NO reply.
>
>> And between the proxy and the client :
>>
>> GET http://www.mopub.com/ HTTP/1.1
>> Host: www.mopub.com
>> User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:17.0) Gecko/20100101
>> Firefox/17.0
>> Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
>> Accept-Language: en-US,en;q=0.5
>> Accept-Encoding: gzip, deflate
>> Proxy-Connection: keep-alive
>
>
> Amos

-- 
Eliezer Croitoru
https://www1.ngtech.co.il
sip:ngtech_at_sip2sip.info
IT consulting for Nonprofit organizations
eliezer <at> ngtech.co.il