I'm designing a custom application, which needs a custom IP packet.

In order to identify the traffic, I need an open protocol number, left for development.

In layer 2, I used the 0x88b5 : "available for public use for prototype development" (source)

Does such a protocol number exist for the IP layer ?

I searched IANA Protocol Registry, but wasn't able to find one.

  • PS : is it the right SE to post this ?
    – 3isenHeim
    Mar 11, 2016 at 15:45

1 Answer 1


You should check the IANA Protocol Registry. It depends on what you want to do. For instance, protocol 61 or 63 may fit. You just need to study to see which one is for you.

  • Could the 253 or 254 be used ? They are for "Experimentation and testing". It won't impact the routing behavior, will it ?
    – 3isenHeim
    Mar 14, 2016 at 7:30
  • 1
    Those are probably fine. Unless there is something like an ACL which blocks those protocols, a router normally doesn't care about the protocol of the packets it is switching.
    – Ron Maupin
    Mar 14, 2016 at 11:57

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.