Hi, One of the differences is when you configure some prefix on lo you get route like this: local 127.0.0.0/8 dev lo ... And with dummy it is not the case. This route type makes kernel consider every address from this space as local - bind on it, reply to pings etc.
On Fri, Apr 27, 2018 at 11:40 AM, Anton Danilov < littlesmilingcl...@gmail.com> wrote: > Hi. > There isn't a difference from perspective of routing. > > On 27 April 2018 at 11:52, Wilhelm Schuster <w...@rot13.io> wrote: > > Hi, > > > > I’m learning about IP-networking and am in the process of setting up a > Linux router using bird. During my research I’ve come across the usage of > loopback interfaces. I could gather that this is done, because Ethernet > interfaces for example (in contrast to loopbacks) can go down making the > addresses configured on them unavailable. In addition, the kernel accepts > packets destined to loopbacks addresses on other interfaces making these > addresses available on multiple interfaces and not just the loopback. > > > > On Linux I found both the lo(opback), and dummy interfaces recommended > to achieve the behavior outlined above. What I’m struggling with is > understanding the differences between both interface types (besides the > obvious difference in packet processing) and when to use which. Searching > this mailing list I’ve seen people use lo, on other sites dummy interfaces > are recommended. From a quick test (assigning address to lo/dummy; > pinging/receiving pings on the host) I wasn’t able to find a difference. > > > > When should I use which interface? > > > > Cheers, Wilhelm. > > > > -- > Anton. > >
