I have Xenserver in version 7.2 with several VM.
I only have 1 nic (eth0). All VM are bridged to xenbr0. I would like to drop some type of packet so in /etc/sysconfig/iptables I added :
-A INPUT -p udp --dport 161 -j DROP
here is the complete file :
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
:RH-Firewall-1-INPUT - [0:0]
-A INPUT -j RH-Firewall-1-INPUT
-A FORWARD -j RH-Firewall-1-INPUT
-A RH-Firewall-1-INPUT -i lo -j ACCEPT
-A RH-Firewall-1-INPUT -p udp --dport 161 -j DROP
-A RH-Firewall-1-INPUT -p icmp --icmp-type any -j ACCEPT
# DHCP for host internal networks (CA-6996)
-A RH-Firewall-1-INPUT -p udp -m udp --dport 67 --in-interface xenapi -j ACCEPT
-A RH-Firewall-1-INPUT -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT
# Linux HA hearbeat (CA-9394)
-A RH-Firewall-1-INPUT -m conntrack --ctstate NEW -m udp -p udp --dport 694 -j ACCEPT
-A RH-Firewall-1-INPUT -m conntrack --ctstate NEW -m tcp -p tcp --dport 22 -j ACCEPT
-A RH-Firewall-1-INPUT -m conntrack --ctstate NEW -m tcp -p tcp --dport 80 -j ACCEPT
-A RH-Firewall-1-INPUT -m conntrack --ctstate NEW -m tcp -p tcp --dport 443 -j ACCEPT
# dlm
-A RH-Firewall-1-INPUT -p tcp -m tcp --dport 21064 -j ACCEPT
-A RH-Firewall-1-INPUT -p udp -m multiport --dports 5404,5405 -j ACCEPT
-A RH-Firewall-1-INPUT -j REJECT --reject-with icmp-host-prohibited
COMMIT
I read here that iptables is bypassed in bridged environnement, do I need to add this rules explicitly on all vif interface ? It doesnt work when I specify xenbr0 as the interface in iptables rule.
