Re: Connecting back to the host through a dummy veth interface

Hi Felix,

On Thu, 18 Dec 2025 13:32:36 +0100

Felix Rubio wrote:

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Hi everybody,

I am trying to run a number of rootless podman pods and containers by different users, while still being able to talk to each other. To this end I am creating a dummy veth interface and publishing all the exposed ports there (this works: I can communicate from other host services with those containers), and I am also trying to set that dummy veth interface as the default gateway for

Hey Stefano, Thank you for your answer! I know I can run rootful containers, and that then I can access the host's network ns. However, this exposes a number of potential issues: * In case the an attacker manages to break out of the container, gets root * That enables connecting back to the host loopback, but then from that container any service listening to the loopback can be reached as well. The reason for looking for a way of binding those services to 10.255.255.1 (so that only exposed services will be in that interface) and running fully rootless, if works, provides a more secure system... in general. About the mapped ports, I am a bit lost: for what I have tested, running rootless disables the possibility to connect back to the host, right? Regards, and thank you! Felix On Saturday, 20 December 2025 15:12:24 Central European Standard Time Stefano Brivio wrote: the

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pods/containers (with the expectation that then they will be able to reach each other). However, this is not working... and I am pretty lost.

For example, I am running the following command, trying to connect a ldap client container to a ldap server container, unsuccessfully.

podman run --rm --dns=10.255.255.1 --network=pasta:--outbound- if4=cluster_dns0,--gateway=10.255.255.1 --add- host=ldap.host.internal:host-gateway sh -c "ip add && ip route && ldapwhoami -H ldaps:// ldap.host.internal:1636"

Is this something impossible to do, or am I doing something wrong?

Sorry, I'm a bit swamped at the moment, and I plan to get back to you in a bit, but meanwhile, I think the dummy veth trick is unnecessarily complicated.

I think you could simply connect "to the host" and redirect from there to the containers by means of mapped ports. See:

https://blog.podman.io/2024/10/podman-5-3-changes-for-improved-networking-ex...

for a couple of details. But I'll try to come up with a full example next.

-- Felix Rubio