I recently started looking into why the number of connected peers was often maxed out and why the traffic increased so much. I found out that the are several actors that constantly connect to your node and drop the connections seconds later (e.g. 52.51.*.*) or block connections slots (e.g. 37.97.164.*).
http://imgur.com/5clGbB4A few of these ip ranges where already mentioned on reddit and almost all ips had abuse reports on AbuseIPDB. I am not sure what these people are trying to do but it is either spying, ddosing and trying to exploit your server.
https://reddit.com/r/Bitcoin/comments/4kbm4r/nodes_are_being_dos_attacked_w_fake_spv_clients/https://reddit.com/r/btc/comments/4gzgqp/are_there_any_operators_of_core_nodes_herehttps://bitco.in/forum/threads/connection-slot-exhaustion-attack.1111/https://abuseipdb.com/check/71.6.135.131Any node operator should ban these ips permantly. That is why I started to collect all malicious nodes and will continue to update this list (
last update 14. June 2016).
IPs:
198.20.69.74
198.20.87.98
71.6.146.185
71.6.135.131
52.17.174.61
52.30.29.120
52.30.204.116
52.51.32.197
52.51.136.220
52.51.170.201
52.51.170.223
52.51.180.197
52.51.186.21
52.51.204.39
52.51.204.55
52.51.204.57
52.51.204.60
52.51.204.88
52.51.204.93
37.97.164.159
37.97.164.160
37.97.164.230
37.97.164.231
82.221.105.7
Iptables (best option since no bitcoind resources are wasted):
iptables -A INPUT -s 198.20.69.74 -j DROP
iptables -A INPUT -s 198.20.87.98 -j DROP
iptables -A INPUT -s 71.6.146.185 -j DROP
iptables -A INPUT -s 71.6.135.131 -j DROP
iptables -A INPUT -s 71.6.146.185 -j DROP
iptables -A INPUT -s 71.6.135.131 -j DROP
iptables -A INPUT -s 82.221.105.7 -j DROP
iptables -A INPUT -s 37.97.164.159 -j DROP
iptables -A INPUT -s 37.97.164.160 -j DROP
iptables -A INPUT -s 37.97.164.230 -j DROP
iptables -A INPUT -s 37.97.164.231 -j DROP
iptables -A INPUT -s 52.17.174.61 -j DROP
iptables -A INPUT -s 52.30.29.120 -j DROP
iptables -A INPUT -s 52.30.204.116 -j DROP
iptables -A INPUT -s 52.51.32.197 -j DROP
iptables -A INPUT -s 52.51.136.220 -j DROP
iptables -A INPUT -s 52.51.170.201 -j DROP
iptables -A INPUT -s 52.51.170.223 -j DROP
iptables -A INPUT -s 52.51.180.197 -j DROP
iptables -A INPUT -s 52.51.186.21 -j DROP
iptables -A INPUT -s 52.51.204.39 -j DROP
iptables -A INPUT -s 52.51.204.55 -j DROP
iptables -A INPUT -s 52.51.204.57 -j DROP
iptables -A INPUT -s 52.51.204.60 -j DROP
iptables -A INPUT -s 52.51.204.88 -j DROP
iptables -A INPUT -s 52.51.204.93 -j DROP
Bitcoin Core Command Line ban is for two years):
bitcoin-cli setban 198.20.69.74 add 63072000
bitcoin-cli setban 198.20.87.98 add 63072000
bitcoin-cli setban 71.6.146.185 add 63072000
bitcoin-cli setban 71.6.135.131 add 63072000
bitcoin-cli setban 71.6.146.185 add 63072000
bitcoin-cli setban 71.6.135.131 add 63072000
bitcoin-cli setban 82.221.105.7 add 63072000
bitcoin-cli setban 37.97.164.159 add 63072000
bitcoin-cli setban 37.97.164.160 add 63072000
bitcoin-cli setban 37.97.164.230 add 63072000
bitcoin-cli setban 37.97.164.231 add 63072000
bitcoin-cli setban 52.17.174.61 add 63072000
bitcoin-cli setban 52.30.29.120 add 63072000
bitcoin-cli setban 52.30.204.116 add 63072000
bitcoin-cli setban 52.51.32.197 add 63072000
bitcoin-cli setban 52.51.136.220 add 63072000
bitcoin-cli setban 52.51.170.201 add 63072000
bitcoin-cli setban 52.51.170.223 add 63072000
bitcoin-cli setban 52.51.180.197 add 63072000
bitcoin-cli setban 52.51.186.21 add 63072000
bitcoin-cli setban 52.51.204.39 add 63072000
bitcoin-cli setban 52.51.204.55 add 63072000
bitcoin-cli setban 52.51.204.57 add 63072000
bitcoin-cli setban 52.51.204.60 add 63072000
bitcoin-cli setban 52.51.204.88 add 63072000
bitcoin-cli setban 52.51.204.93 add 63072000
Bitcoin Core Debug Console (ban is for two years):
setban 198.20.69.74 add 63072000
setban 198.20.87.98 add 63072000
setban 71.6.146.185 add 63072000
setban 71.6.135.131 add 63072000
setban 71.6.146.185 add 63072000
setban 71.6.135.131 add 63072000
setban 82.221.105.7 add 63072000
setban 37.97.164.159 add 63072000
setban 37.97.164.160 add 63072000
setban 37.97.164.230 add 63072000
setban 37.97.164.231 add 63072000
setban 52.17.174.61 add 63072000
setban 52.30.29.120 add 63072000
setban 52.30.204.116 add 63072000
setban 52.51.32.197 add 63072000
setban 52.51.136.220 add 63072000
setban 52.51.170.201 add 63072000
setban 52.51.170.223 add 63072000
setban 52.51.180.197 add 63072000
setban 52.51.186.21 add 63072000
setban 52.51.204.39 add 63072000
setban 52.51.204.55 add 63072000
setban 52.51.204.57 add 63072000
setban 52.51.204.60 add 63072000
setban 52.51.204.88 add 63072000
setban 52.51.204.93 add 63072000