[Iftop-users] iftop resolving IPs as local hostname instead of regular public PTR

[Hoggins!]

Hi there,

First time posting here, I'm having questions/issues regarding DNS PTR 
resolution when running iftop.
I'm asking this because "it used to work" and now it's not outputting 
what I expect, and I'd like to understand why and how to circumvent the 
problem.

I'm aware that my issue might very well be system-related, but I'm sure 
discussing this with you will enable me finding the culprit.

Here's the thing:

I have dynamic (public) IPs attached to a system (using Keepalived, 
everything works fine), and I monitor the traffic going on this public 
interface with iftop. These public IPs all have correct PTR records. 
eg.with dig :

    ;; ANSWER SECTION:
    50.52.196.5.in-addr.arpa. 86369    IN    PTR    www.radiom.fr.


But when I use iftop to monitor this public interface, all I get as 
resolved hostname is my local hostname.
It *used* to work, and I'm pretty sure it's due to a system upgrade, 
maybe a library that doesn't behave as I expect it to.

I checked my /etc/hosts file, but there are no entries linking public 
IPs and the local hostname.

So my question is: where should I look to get the correct info? Is iftop 
using something like gethostbyaddr() to get the hostname?

Thanks!

     Hoggins!