Firewalls

iptables

Open port 161/UDP : edit /etc/sysconfig/iptables

-A INPUT -p udp -s 10.200.0.1 --dport 161 -j ACCEPT
-A INPUT -p udp -s 10.200.0.2 --dport 161 -j ACCEPT

Then reload

service iptables reload

firewalld

Display actives zones only, or all zones

firewall-cmd --list-all
firewall-cmd --list-all-zones

Open port 161/UDP in the default zone, cold (aka --permanent) then live after reload

firewall-cmd --add-port 161/udp --permanent
firewall-cmd --reload

Add tftp service for zone work, aka port 69/UDP plus nf_conntrack_tftp module as defined in /usr/lib/firewalld/services/tftp.xml

firewall-cmd --add-service tftp --zone work