No outbound filters, this is my config:

*filter

:INPUT ACCEPT [0:0]

:FORWARD ACCEPT [0:0]

:OUTPUT ACCEPT [0:0]

-A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT

-A INPUT -p icmp -j ACCEPT

-A INPUT -i lo -j ACCEPT

-A INPUT -p tcp -m comment --comment "SSH" -s x.x.x.x -m state --state NEW -m tcp --dport 22 -j ACCEPT

-A INPUT -p tcp -m comment --comment "Tor" -m state --state NEW -m tcp --dport 80 -j ACCEPT

-A INPUT -p tcp -m comment --comment "Tor" -m state --state NEW -m tcp --dport 443 -j ACCEPT

-A INPUT -j REJECT --reject-with icmp-host-prohibited

-A FORWARD -j REJECT --reject-with icmp-host-prohibited

COMMIT

If I stop tor then "dig @127.0.0.1 google.com" works 100%. It's seems like the pattern is that when tor traffic builds up so do DNS failures. And then my dig @127.0.0.1 only succeeds about 0.1% of the time. At this stage large amounts these errors start appearing:

> Jan 17 19:27:33 torexit unbound: [559:0] notice: remote address is 192.42.93.30 port 53
> Jan 17 19:27:33 torexit unbound: [559:0] notice: sendto failed: Operation not permitted