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[Eucalyptus Beginner’s Guide – UEC edition] Chapter 8 – Security

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Chapter 7
Network Management
Chapter 9
Troubleshooting

Eucalyptus provides ingress filtering for the instances based on the concept of security groups. A Security Group is a named set of rules that Eucalyptus applies to the incoming packets for the instances in Managed and Managed-NOVLAN modes. You can specify a security group while launching an instance. Each security group can have multiple rules associated with it. Each rule specifies the source IP/network, protocol type, destination ports etc. Any packet matching these parameters specified in a rule is allowed in. Rest of the packets are blocked.

A security group that does not have any rules associated with it causes blocking of all incoming traffic.

The mechanism only provides ingress filtering and does not provide any egress filtering. As a result all outbound traffic is allowed. If you need to implement egress filtering, you will need to implement that inside the instance using a firewall.

Tools like Hybridfox let you manage security groups and also let you specify a security group while launching an instance.

Here are a few euca commands to manage security groups:

Create a security group named “webservers” :

uecadmin@client1:~$ euca-add-group -d "Web Servers" webservers

Add a rule to the security group “webservers” allowing icmp and tcp traffic from a.b.c.d :

uecadmin@client1:~$ euca-authorize -P tcp -s a.b.c.d webservers
uecadmin@client1:~$ euca-authorize -P icmp -s a.b.c.d webservers

The added rules can be viewed with euca-describe-groups command

$ euca-describe-groups
GROUP   admin   default default group
GROUP   admin   webservers      Web Servers
PERMISSION      admin   webservers     ALLOWS  icmp    -1      -1      FROMCIDR     0.0.0.0/0
PERMISSION      admin   webservers     ALLOWS  tcp     22      22      FROMCIDR     0.0.0.0/0

Launch an instance associated with the security group “webservers” :

uecadmin@client1:~$ euca-run-instances emi-XXXXXXXX -k mykey -g webservers

List the details of the existing security groups :

euca-describe-groups

Remove the rule for icmp traffic from the source ip a.b.c.d from the security group “webservers” :

uecadmin@client1:~$ euca-revoke -P icmp -s a.b.c.d webservers

Delete the security group “webservers” :

euca-delete-group webservers
Chapter 7
Network Management
Chapter 9
Troubleshooting
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