I am working with CentOS 7 OS hosting a set of docker containers.
By using a web browser I can reach a service on port 80 and I get back a response. A bit of local knowledge helps me understand that the response comes from one of the docker containers.
However, I have a big problem: I can't seem to find a way for the OS to indicate that port 80 is open.
Here is what I have tried (all with
netstat -tulnp | grep 80lists nothing listening on port 80
ss -nutlp | grep 80lists nothing listening on port 80
lsof -i -P | grep 80also lists nothing listening on port 80
wget 127.0.0.1successfully fetches index.html
Interrogating Docker directly through
docker ps is not really the answer I am looking for, because we must be able to interrogate the OS and see what process is responsible for treating requests to port 80. It's also not helpful, because
docker ps returns several containers that have the following entry in the PORTS column:
PORTS 80/tcp 8080/tcp 80/tcp
Again, I don't want to go to docker for answers, because there must be a way to interrogate the OS and identify the process responsible for handling port 80.
My only guess is that docker installs some sort of low-level driver that intercepts such network requests.
Any suggestions on how to get CentOS to hand out this information, accompanied with command line commands, would be greatly appreciated!