AWS S3 file read from specific bucket with SSL


I just started using Knime and really like it. I’m having a problem with connecting to S3 and reading a number of CSV files using URLs. My flow is as follows:

  1. Connect to S3 (works)
  2. List files (works)
  3. Convert list to flow variables (works --> converts to https URL, which is what I use)
  4. File Picker to get the file (works)
  5. CSV Reader to read the CSV (fails here, see below)

The url created for the file has the following form:

https://****<security signature/creds/etc.>

This URL is provided as a flow variable, and, when the CSV reader tries to read this URL, it fails. The logs show the following errors: No subject alternative DNS name matching found`
Caused by: No subject alternative DNS name matching

I used a browser and openssl to look at the security certificate, and I see that this error is indeed correct: there is no name for my bucket in the SSL certificate. That’s to be expected, since AWS can’t know how I’ll name my buckets. SO, they use a wildcard name in the certificate:


When I go to my browser and put in the full URL that was created by the flow variable, I am able to easily download the file.

I went on these forums to see how to solve this, and it looks like the SSLHandshake error has occurred before. The fix seems to be to import the certificate into the local keystore. However, when I try to import the certificate chain into my Knime keystore located in my (windows install here!) \Program Files\KNIME\plugins\org.knime.binary.jre.win32.x86_64_1.8.0.202-b08\jre\lib\security\cacerts , I still get the error. I’ve verified that the cert chain that imported is present by listing the certs in the keystore and looking for the fingerprint-- it’s there. I’ll note however, that I gave the cert an alias (“aws_test”), so I’m not sure if that changes anything.

Does anyone have any thoughts on how I might fix this? What have I done wrong? Clearly, the browser honors the wildcard name on the cert, while Knime seems to have a problem with it. Could I address this with an LMHOSTS entry?

Thanks (in advance).


@rnknime, Hope this helps -


How to Access S3 via https URLs

As pointed out above, there are two forms of S3 URLs that work with https:

and this:

So, in order to get https to work seamlessly with your S3 buckets, you need to either:

  • choose a bucket whose name contains no periods and use the virtual host URL, such as or
  • use the URL form that specifies the bucket name separately, after the host name, like this: .

Update 25 Aug 2009: For buckets created via the CreateBucketConfiguration API call, the only option is to use the virtual host URL. This is documented in the S3 docs here.

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Tested S3 workflow on similar lines mentioned above -

NOTE: I am using access key for S3 connection.

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Hi @rnknime,

another option would be the Download node to download the files and optional the Create Temp Dir node as local download directory. This uses the S3 connection instead of signed URLs.


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