invalid response from Proxy dns lookup failure in my domains

[Dan Sheffner]

A work around the DNS is editing the /etc/hosts file and hard coding your
servers there.  Do you have access to this file?


On Mon, Jan 10, 2011 at 9:08 AM, Tapas Mishra <mightydreams at gmail.com>wrote:

> On Mon, Jan 10, 2011 at 5:31 PM, Tapas Mishra <mightydreams at gmail.com>
> wrote:
> > Hi all.
> > The problem I am reporting is not very clearly evident to me.
> > I have a virtualization setup where in I had configured in 4 virtual
> > machines (which serve 4 different websites)  available to internet via
> > a
> > Reverse Proxy on the Host OS (bare metal) I use Ubuntu 10.04 64 bit
> > server edition and kvm for this setup.
> >
> > We have not changed any of the server configurations from past 6
> > months since things were working properly without any problem on this
> > server.
> > The sites are available to people as
> >
> >
> > http://site1.myserver.com <-- No problem
> > http://site1.myserver.com/app1 <-- Gives problem till weekend there
> > was no problem
> >
> > http://site4.myserver.com   <--Is also giving problem till this Sunday
> > 9 Jan there were no problem.
> >
> > Here are the error messages which I see in Apache logs
> >
> > Mon Jan 10 17:07:05 2011] [error] [client 172.21.100.250] proxy: DNS
> > lookup failure for: site4.myserver.com returned by /
> > [Mon Jan 10 17:07:06 2011] [error] [client 172.21.100.250] proxy: DNS
> > lookup failure for: site4.myserver.com returned by /
> >
> > and for site1.myserver.com/app1 also I get same error
> >
> > [Mon Jan 10 17:06:01 2011] [error] [client 172.21.100.250] proxy: DNS
> > lookup failure for: site1.myserver.com returned by /app1/
> > [Mon Jan 10 17:06:01 2011] [error] [client 172.21.100.250] proxy: DNS
> > lookup failure for: site1.myserver.com returned by /app1/
> > [Mon Jan 10 17:06:02 2011] [error] [client 172.21.100.250] proxy: DNS
> > lookup failure for: site1.myserver.com returned by /app1/
> >
> >
> > How ever when some one tries to access http://site1.myserver.com there
> > is no error at all.
> > Also if I access  http://site5.somebody_server.com (which is same as
> > http://site4.myserver.com pointing to same public IP) but on some body
> > elses server
> > then there is no problem at all and the site is very clearly visible.
> >
> >
> > Let me know what more should I look for I have no clue of this problem.
> > Because these error messages which I just report in this thread were
> > not at all present until today  morning.
> >
> >
> >
> > --
> >
>
> Ok after having a long trouble shooting hours found the root cause
>  my proxy pass entries look as follows
>
>  ProxyPass /app1 http://192.168.1.3:8080/app1
>  ProxyPass / http://192.168.1.3
>  ProxyPassReverse /app1 http://192.168.1.3:8080/app1
>  ProxyPassReverse / http://192.168.1.3
>
> If I use the entries as above then some one from internet is able to
> access the sites.But from within LAN people are unable to access it.
>
> How ever if I use
>
>  ProxyPass /app1 http://site1.myserver.com:8080/app1
>  ProxyPass / http://site1.myserver.com
>  ProxyPassReverse /app1 http://site1.myserver.com:8080/app1
>  ProxyPassReverse / http://site1.myserver.com
>
> then things work on LAN but from internet it is not accessible and
> errors are the ones I mentioned above in the thread.
>
> What can be a solution in this case as I do not have a DNS at my
> disposal I am simply not allowed to have one.
> Can some one suggest any thing?
>
> --
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