I'm having issues reaching the 'old' Secure DNS servers also.
Pinging 156.154.70.22 with 32 bytes of data:
Request timed out.
Reply from 156.154.70.22: bytes=32 time=27ms TTL=51
Request timed out.
Request timed out.
Request timed out.
It seems to be resolving DNS query's though
C:\Data>nslookup www.comodo.com. 156.154.70.22
Server: UnKnown
Address: 156.154.70.22
Non-authoritative answer:
Name: www.comodo.com
Address: 91.199.212.176