iproute-doc software package provides transitional dummy package for iproute2-doc, you can install in your Debian 9 (Stretch) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install iproute-doc
iproute-doc is installed in your system.
Make ensure the iproute-doc package were installed using the commands given below,
$ sudo dpkg-query -l | grep iproute-doc *
You will get with iproute-doc package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Old Libraries |
| Package | iproute-doc |
| Version | 1:4.8.0-1 |
| Description | transitional dummy package for iproute2-doc |
| Sub Section | Oldlibs |