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Error - Failed to connect to localhost:19006

Scott | Last updated: Dec 05, 2023 01:15PM UTC

This is my first time using Burp Suite, and have a trial of the pro version. I am trying to test my company's web app for security vulnerabilities. I have a version of the app running on http://localhost:19006/. When I access this from any normal browser, it loads just fine. However, when I open the built-in Burp Suite browser I am hit with the error shown in the title of this post. I've tried with intercept on (and then forwarding the request) and intercept off. Not sure what is wrong, as this doesn't seem like a common issue from what I can find online. The request that gets sent is as follows, there is no response after: """ GET / HTTP/1.1 Host: localhost:19006 sec-ch-ua: "Chromium";v="119", "Not?A_Brand";v="24" sec-ch-ua-mobile: ?0 sec-ch-ua-platform: "Windows" Upgrade-Insecure-Requests: 1 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/119.0.6045.199 Safari/537.36 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7 Sec-Fetch-Site: none Sec-Fetch-Mode: navigate Sec-Fetch-User: ?1 Sec-Fetch-Dest: document Accept-Encoding: gzip, deflate, br Accept-Language: en-GB,en-US;q=0.9,en;q=0.8 Connection: close """

Michelle, PortSwigger Agent | Last updated: Dec 05, 2023 04:10PM UTC

Hi I didn't see the same behavior when I tested a similar setup here. Can you tell me more about your setup? Is Burp set to use an upstream proxy? Is the site available via a browser that isn't proxied via Burp at the time you cannot connect via Burp? Are you able to connect to other sites using Burp's embedded browser? If it would help to share some screenshots to explain what you are seeing, feel free to email them to support@portswigger.net

Scott | Last updated: Dec 06, 2023 07:42AM UTC

"Is Burp set to use an upstream proxy?" - Not sure. I haven't changed anything away from whatever the defaults are. I selected the default option on startup. "Is the site available via a browser that isn't proxied via Burp at the time you cannot connect via Burp?" - Yes, as mentioned I can load the app just fine in any browser, both before and after attempting to load the exact same thing in Burp's embedded browser. "Are you able to connect to other sites using Burp's embedded browser?" - Yes, the browser works fine otherwise. I sent a screenshot to that email, with the same title as this post. If you need more details on how the app is started I can elaborate on there.

Michelle, PortSwigger Agent | Last updated: Dec 06, 2023 08:59AM UTC

Hi We've got your email so we'll take a look through and be in touch soon.

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