En ce qui me concerne, aucun problème pour pinger les dNS Bouygues du réseau Free. Aucune perte de paquet et un temps de réponse d'environ 20 ms, normal.
Edit : un petit exemple :
~$ ping 194.158.122.15
PING 194.158.122.15 (194.158.122.15) 56(84) bytes of data.
64 bytes from 194.158.122.15: icmp_seq=1 ttl=246 time=24.2 ms
64 bytes from 194.158.122.15: icmp_seq=2 ttl=246 time=23.0 ms
64 bytes from 194.158.122.15: icmp_seq=3 ttl=246 time=10.7 ms
64 bytes from 194.158.122.15: icmp_seq=4 ttl=246 time=25.6 ms
64 bytes from 194.158.122.15: icmp_seq=5 ttl=246 time=16.7 ms
64 bytes from 194.158.122.15: icmp_seq=6 ttl=246 time=11.5 ms
^C
--- 194.158.122.15 ping statistics ---
6 packets transmitted, 6 received, 0% packet loss, time 5009ms
rtt min/avg/max/mdev = 10.710/18.643/25.634/5.999 ms