Re: DNS problem

On Thu, 2006-10-26 at 12:35 +0530, Jegadeesh wrote:

> We tried running the test bed with the IP address configured instead
> of domain names as you mentioned.It is working.

Good!

> Yes, we need to send the host headers to the proxy so that it will
> select the correct origin server. Our test bed should use the names
> instead of the addresses

If you want the Host: header to be a domain name that your proxy can map
into several origin server addresses, then you cannot avoid placing that
domain name in PGL Map.names. In this case, Polygraph will have to
resolve the name.

If real DNS resolution does not work at all, then you will need to
figure out why the configured DNS resolver is not getting Polygraph DNS
queries or why Polygraph is not getting the responses. You can try a
manual test with dig (bound to a polyclt IP alias!) to troubleshoot.

If real DNS resolution works, but generates too many errors/timeouts due
to overload, I see two options (besides checking the network cable :-):

1) Hack Polygraph sources to avoid the resolution for all or a
hard-coded set of domain names. The response(s) will be hard-coded. This
should work fine for a one-time test.

2) Teach Polygraph to use the PGL address map to resolve names without
sending any DNS queries. This option is more work, but is the right
solution, especially if the testing is not confined to a couple of
weeks.

In either case, your team can hack Polygraph sources or ask the Factory
to do the work.

HTH,

Alex.

> On 10/26/06, Alex Rousskov <rousskov@measurement-factory.com> wrote:
> On Thu, 2006-10-26 at 01:13 +0530, Jegadeesh wrote:
>
> > We have attached the DNS configuration in workload file.
> >
> > AddrMap Map = {
> > addresses = [ '172.16.X.101:80', '172.16.X.101:80',
> > '172.16.X.101:80', '172.16.X.101:80', '172.16.X.101:80' ];
> > names = [ 'www[1-5].mycompany.com:80' ];
> >
> > };
> >
> > DnsResolver dr = {
> > servers = [ '172.16.X.X:53' ];//DNS server IP and Port
> > timeout = 05sec;
> > };
> >
> > Robot R = {
> > .......................
> > .......................
> >
> > dns_resolver = dr;
> > };
> >
> > Is there any wrong. Please help me.
>
> Is there a reason you want to put domain names in Map.names?
> Can you
> just put IP addresses there? For example,
>
> AddrMap = {
> addresses = ...;
> names = addresses;
> };
>
> And if your map is 1:1, you can get rid of it by specifying IP
> addresses
> in R.origins .
>
> If the above does not work, we would need to teach Polygraph
> how to
> resolve addresses using the AddrMap, without making actual DNS
> queries.
>
> HTH,
>
> Alex.
>
>
>
Received on Thu Oct 26 11:59:02 2006