Score:0

Find all firewalled connections from a binary from the client

cn flag

I have a binary file that is failing with no helpful information. It works in the prod domain, but it is failing in the dev domain. I believe it is failing due to firewall rules. I'd like to figure out what cross-domain firewall exceptions to request.

Is there a way to capture what failed connections it is attempting when I run the binary? That is, from the client rather than the looking at the firewall logs.

(RedHat 7 environment)

Score:0
de flag

You can try to trace network system calls produced by your program:

strace -f -e trace=network ./yourprogram

You should be able to see connect system calls produced by your program. Take note of IP address (sin_addr) and the port (sin_port) on these lines.

Further, you can run tcpdump to look inside traffic to those IP:port:

tcpdump -i any host FILTERED_IP and port FILTERED_PORT
cn flag
Thanks. This let me rule out firewall issues.
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