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https://issues.apache.org/jira/browse/CLOUDSTACK-4675?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14237683#comment-14237683
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Abhinandan Prateek edited comment on CLOUDSTACK-4675 at 12/8/14 9:44 AM:
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cloud-early-config is the one configuring the services on VR, this will 
override manual conf changes to dnsmasq. 


was (Author: aprateek):
cloud-early-config is the one configuring the services on VR, this will 
override conf changes to dnsmasq. 

> Virtual Router only with DHCP should not have DNS service
> ---------------------------------------------------------
>
>                 Key: CLOUDSTACK-4675
>                 URL: https://issues.apache.org/jira/browse/CLOUDSTACK-4675
>             Project: CloudStack
>          Issue Type: Bug
>      Security Level: Public(Anyone can view this level - this is the 
> default.) 
>          Components: Virtual Router
>    Affects Versions: 4.1.1
>            Reporter: France
>
> When one creates a virtual router using only DHCP as service one gets also 
> DNS service, because dnsmasq.conf service has DNS service enabled. It can be 
> disabled by setting port=0, but it's not.
> This assumption that there is no open recursive DNS service present, can lead 
> user to exposing open resursive DNS server to untrusted hosts, which then 
> abuse it for DNS amplification attack.
> Please actually disable DNS service, if it's not selected when creating 
> network offering.
> As a workaround i've added below commands to rc.local. Fix directly 
> dnsmasql.conf gets reverted by some cloud init scripts.
> iptables -I INPUT -p udp --dport 53 -j DROP
> iptables -I INPUT -p tcp --dport 53 -j DROP



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