Should not try to resolve address when connecting through HTTP proxy

[cyberduck]

de76d1c created the issue

We are trying to use Cyberduck to connect to an S3 compatible provider via our Proxy solution. We set the settings to use system proxy and put in all the information for the connection. We use our proxy to do DNS resolution for external URL's and not our internal DNS servers. When we try and connect to the S3 bucket we get a DNS resolution error that is cannot resolve the DNS name for the Storage URL on the internet. I think what is happening is Cyberduck is trying to get DNS from the internal DNS servers configured in the OS and not allowing the Proxy to provide the lookup. Can you provide some support on this?

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Attachments

• Ticket 8733 - Verizon S3 Storage URL.docx (142.0 KiB)

[cyberduck]

@dkocher commented

A HTTP proxy server does not provide DNS resolution. Provide a DNS server IP address in TCP/IP system settings that can resolve the DNS name.

[cyberduck]

de76d1c commented

:) Actually in our case it does. We don't allow our internal DNS servers to resolve external addresses for security reasons and all external resolution is done by our Zscaler Proxies. So the issue we are running into with Cyberduck is that Cyberduck is trying to resolve using the DNS servers set on OS and not resolution coming from Proxy. We have tested another tool called Cloudberry Explorer and that works with our proxy but does not offer a Linux version which is an issue for us. Would come one be willing to work with us to try and resolve?

[cyberduck]

@dkocher commented

Please post the system configuration proxy settings.

[cyberduck]

@dkocher commented

We are connecting to an S3 compatible storage bucket on Verizon. We are reaching to the internet through our Proxy and our Proxy does the DNS resolution  on traffic going out. I think what is happening is that Cyberduck is doing DNS lookups via the DNS servers set on the system (Internal) and not allowing the Proxy to provide the lookup. So when Cyberduck does the DNS request for storage-iad3a.cloud.verizon.com and uses the internal servers, it is not able to resolve. We don’t allow internal DNS servers to resolve external addresses. What we need is Cyberduck to get the DNS lookup form the Proxy on Port 80.

When connecting through the HTTP proxy the target hostname storage-iad3a.cloud.verizon.com should just be passed in the CONNECT header and not be resolved. The hostname will be resolved by the proxy and Cyberduck does no DNS lookup for the target server at all but only for the proxy.

[cyberduck]

de76d1c commented

Can we chat on the phone to discuss?

[cyberduck]

@dkocher commented

In cbe5337. Please update to the latest snapshot build available.

[cyberduck]

de76d1c commented

Is that a Linux update version as well?

[cyberduck]

@dkocher commented

Replying to [comment:8 brian.w.walker@…]:

Is that a Linux update version as well?

Snapshot builds for Cyberduck CLI for Linux will be available within a few minutes.

[cyberduck]

@dkocher commented

Replying to [comment:6 brian.w.walker@…]:

Can we chat on the phone to discuss?

We prefer to keep the conversation documented in this thread for future reference.

[cyberduck]

de76d1c commented

ok, I am running Ubuntu 14.04. I am not an ubuntu expert. Can you give me the exact commands to run to grab th new package and install?

[cyberduck]

@dkocher commented

Replying to [comment:11 brian.w.walker@…]:

ok, I am running Ubuntu 14.04. I am not an ubuntu expert. Can you give me the exact commands to run to grab th new package and install?

Please follow our instructions to use the DEB Package Repository with the nightly source added.

[cyberduck]

de76d1c commented

We grabbed the new version. Can you help with Command Line for connecting to Verizon using our access and private key?

[cyberduck]

de76d1c commented

Will the Linux version use the proxy settings on execution, or do we need to configure the linux CLI to use the proxy?

[cyberduck]

@dkocher commented

Replying to [comment:14 brian.w.walker@…]:

Will the Linux version use the proxy settings on execution, or do we need to configure the linux CLI to use the proxy?
Good point. Added default proxy finder implementation that should work on Linux in 09121bc.