Re: [squid-users] Strange problem with 503 errors.

On 06/04/2012 07:55, Michael D. Setzer II wrote:
> My college recently switched from ISP provided IPs to its own.
> 202.128.71.x, 202.128.72.x, 202.128.73.x and 202.128.79.x from
> ISP to there own 203.215.52.0/22.
>
> The switch seemed to go fine, but have found a few sites that are
> giving us 503 errors.
>
> I have gotten around the problem by using rinetd to redirect a port
> to the squid server on my home machine for these sites, and one
> of our ISPs has given access to there proxy server so now using
> that, but ideally would like to come up with what is causing the
> problem.
>
> I have squid servers on campus, and was wondering if there was
> a way to have them in the event of not being able to connect to a
> site, it they could automatically try going thru the ISPs proxy?
>
> The traceroutes to the sites that don't work get to the point right
> before they should, 1 hop less. The latest problem site is strange.
>
> Going to tinyurl.com sometimes gives the IP address
> 64.62.243.89, which works fine. But other times it gives
> 64.62.243.91, which doesn't from the college. Both work fine from
> home. In running wireshark, the 89 address will send and receive
> pings and responses, but the 91 only shows the sends with no
> receive responses.
>
Well the problem is on the network layer... ip.. if you can't ping you
can't connect.
so your college need to contact his ISP and get some answers about it.
as more he has more detailed info about the problem the more he can get
with.
also he must get someone that actually knows something about the ISP
network and not to just talk with someone who will not have any
privilege or knowledge about the system.

Regards,
Eliezer

> nmap shows no open ports on the 91 from college, but from home
> it does? Perhaps someone might have a way of figuring out what
> the issue is. Our IT guys say they are not blocking these IPs, and
> even they have found sites that don't work for them.
>
> Thanks.
>
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> Michael D. Setzer II - Computer Science Instructor
> Guam Community College Computer Center
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> mailto:msetzerii_at_gmail.com
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> http://sourceforge.net/projects/g4l/
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-- 
Eliezer Croitoru
https://www1.ngtech.co.il
IT consulting for Nonprofit organizations
eliezer <at> ngtech.co.il