One thing that's very misunderstood about URONode is that people seem to think
it handles kernel routines such as node broadcasts and receptions into the
netrom nodes tables. It does not! It's a user front-end that relies on the
kernel's tables for connectivity and nodes listings which is why it's such
a fast node rather than trying to run another protocol stack on top of an
existing one. In any event I have derived the following iptables rules
that will help filter out incoming nodes broadcasts that are not wanted.
Keep in mind you also must allow those who you wish to link with in:

# BPQ udp 10093 and node injection filter rules:
/sbin/iptables -I INPUT -s 0.0.0.0/0 -j DROP -p udp --dport 10093 -d 0.0.0.0/0
# axudp
/sbin/iptables -I INPUT -s 0.0.0.0/0 -j DROP -p udp --dport 93 -d 0.0.0.0/0
# axip
/sbin/iptables -I INPUT -s 0.0.0.0/0 -j DROP -p 93 -d 0.0.0.0/0

# now add those you intend to allow:
/sbin/iptables -I INPUT 1 -s 173.218.33.215 -j ACCEPT -p udp --dport 10093 -d 0.0.0.0/0
/sbin/iptables -I INPUT 1 -s 74.69.112.177 -j ACCEPT -p udp --dport 93 -d 0.0.0.0/0
/sbin/iptables -I INPUT 1 -s 44.88.0.9 -j ACCEPT -p 93 -d 44.88.0.1
/sbin/iptables -I INPUT 1 -s 44.131.244.1 -j ACCEPT -p 93 -d 44.88.0.1

Remember to do your denials first before the accept/allows.
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