Symptom:

Various symptoms :
1) Hostname in the status line (final line next to system name) is truncated.
2) Hostname in the ABAP/4 field Sy-Subrc is truncated.
3) RFC connections with the destination NONE cause the error message : "Unable to determine host address: NiHostToAddr failed..."
4) Error in application programs which work with these hostnames, for example ST02.

Cause and prerequisites

Internal restriction in the SAP System.

Solution
To be on the safe side, the hostname of a computer (command hostname or
uname -a) should not be longer than 8 letters in older releases.
Please refer to the installation guide or upgrade guide to find the
maximum hostname lengths in the relevant release.