My relays have been patched to the latest available kernels, and aren't in the list of vulnerable relays, however they still show high values for TCPSYNChallenge:
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$ ansible tor -a 'bash -c "netstat -s | grep -i challenge"' -b --ask-become-pass
lon | SUCCESS | rc=0 >> TCPChallengeACK: 14197 TCPSYNChallenge: 2926
fra | SUCCESS | rc=0 >> TCPChallengeACK: 12907 TCPSYNChallenge: 3461
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$ ansible tor -a 'bash -c "cat /etc/lsb-release && uname -rv"' -b --ask-become-pass
fra | SUCCESS | rc=0 >> DISTRIB_ID=Ubuntu DISTRIB_RELEASE=14.04 DISTRIB_CODENAME=trusty DISTRIB_DESCRIPTION="Ubuntu 14.04.5 LTS" 3.13.0-101-generic #148-Ubuntu SMP Thu Oct 20 22:08:32 UTC 2016
lon | SUCCESS | rc=0 >> DISTRIB_ID=Ubuntu DISTRIB_RELEASE=14.04 DISTRIB_CODENAME=trusty DISTRIB_DESCRIPTION="Ubuntu 14.04.5 LTS" 3.13.0-101-generic #148-Ubuntu SMP Thu Oct 20 22:08:32 UTC 2016
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