On Sunday 12 October 2025 at 16:05:22, Peter via Dng wrote:

> "ip link set <interface> up" is equivalent to "ifup <interface>"?

I would say that it's the equivalent of "ifconfig <interface> up".

It doesn't set the address, or any routing; it assumes these are already
defined, and it simply brings the link up (ie: makes the interface
operational).

"ifup" takes the configuration defined in /etc/network/interfaces and applies it
to the interface - this brings it up, yes, but also generally configures an
address (or invokes a DHCP client to acquire an address) and may well set a
gateway (route) as well. There can also be arbitrary commands executed before
or after bringing the interface up (again, defined in /etc/network/interfaces).

> Can ifup do something which ip can not do?

"ifup" does several things in one go, All those things can be done using "ip"
commands instead, but I don't know if any single command which does everything
you'd expect from "ifup".

> Is the line beginning "ifup" in the table here incorrect?
> https://en.wikipedia.org/wiki/Iproute2

I'd say it is very over-simplified.


Antony.

--
The difference between theory and practice is that in theory there is no
difference, whereas in practice there is.

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