Detect Newly Created NetNS

Case

• Follow namespaces that appear after the capture starts, just like test_netns_newly_normal.sh.
• Handy for integration tests where ephemeral namespaces are created dynamically.
• Monitor network activity in dynamically created environments, such as CI/CD pipelines or ephemeral test setups.
• Track network communication of applications that create isolated network namespaces for security or resource management.
• Debug network issues in container orchestration systems where new network namespaces are frequently provisioned.

Command

sudo ptcpdump -i any  --netns newly 'icmp'

Start ptcpdump first, then add namespaces and generate traffic—for example using the helper from test_netns_newly_normal.sh that creates veth pairs and pings between 192.168.64.1 and 192.168.64.2. ptcpdump automatically attaches to the new namespaces and records the bidirectional ICMP exchanges.