Gns3 lỗi server error from 127.0.0.1 8000 r1 operation canceled năm 2024

I downloaded GNS3 and successfully installed the latest version (2.0.3) on my laptop that is running on Windows 7 Professional Service Pack 1 (64 bit). I got an error while trying to connect to the server “Error when connecting to the GNS3 server: Cannot connect to http://127.0.0.1:3080. Please check if GNS# is allowed in your antivirus and firewall. And that server version is 2.0.3.”

Error-when-connecting-to-GNS3-server

How to fix the error:

I tried to google a number of blogs to help me fix the error and finally got the fix. From my research, it appeared that this error happens when you first run GNS network simulator on a Windows as well as Linux operating system environment.

The simple fix before you check your anti-virus (McAfee 8.0.0.8093 as for my case) and firewall software, run GNS3 as an administrator and it works perfectly.

Error-when-connecting-to-GNS3-server-fix

This fix works well to resolve the error “could not connect to 127.0.0.1 on port 800: [WinError 10061]No connection could be made because the target machine actively refused it.” This error occurs when you drag and drop some devices like router on the GNS3 network simulator. Read More on this article.

Another type of log when things go south for the Dynamips node when trying to stop it leading to the operation being automatically cancelled

Aug 12 14:44:06.793 CPU0: IO_FPGA: read from unknown addr 0x16, pc=0x60916c6c (size=2)
Aug 12 14:44:06.793 CPU0: IO_FPGA: write to unknown addr 0x16, value=0x1, pc=0x60916c74 (size=2)
Aug 12 14:44:06.829 ROM: trying to read bootvar 'ROM_PERSISTENT_UTC'
Aug 12 14:44:06.957 CPU0: JIT: flushing data structures (compiled pages=1095)
Aug 12 14:44:07.504 ROM: trying to set bootvar 'BSI=0'
Aug 12 14:44:07.504 ROM: trying to read bootvar 'RET_2_RCALTS'
Aug 12 14:44:07.504 ROM: trying to set bootvar 'RET_2_RCALTS='
Aug 12 14:44:07.575 CPU0: JIT: partial JIT flush (count=794)
Aug 12 14:44:07.584 ROM: trying to read bootvar 'RANDOM_NUM'
Aug 12 14:44:16.083 VTTY: Console port is now connected (accept_fd=19,conn_fd=25)
Aug 12 14:44:56.935 CPU0: JIT: flushing data structures (compiled pages=1105)
Aug 12 14:46:43.082 ROM: trying to set bootvar 'RANDOM_NUM=830978794'
Aug 12 18:35:56.880 C3725_STOP: stopping simulation.
Aug 12 18:35:56.880 CPU0: CPU_STATE: Halting CPU (old state=0)...
Aug 12 18:35:56.932 DEVICE: Removal of device WIC-2T(0), fd=-1, host_addr=0x0, flags=0

Then GNS3 loops for a very long time when trying to close the project leading to the type of error described in this with slightly different messages: