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| − | = THIS PAGE IS A DRAFT, NOT A REAL COURSE PAGE =
| + | [http://wiki.littlesvr.ca/wiki/OPS345_Lab_2 This page has moved.] |
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| − | ''' The current schedule for OPS345 is here: [[OPS335_Weekly_Schedule]]
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| − | = AWS Networking =
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| − | * VPCs, subnets
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| − | * Default dynamic public IP
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| − | * Default private network/IP
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| − | * Reserving a static public IP under "Elastic IPs", cost of doing that
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| − | * VPC dashboard:
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| − | ** https://docs.aws.amazon.com/vpc/latest/userguide/VPC_Internet_Gateway.html
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| − | ** New VPC vpc-ops345 with CIDR block 10.3.45.0/24, no IPv6
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| − | ** Subnets: create a new one in vpc-ops345 named subnet-ops345, in us-east-1a, 10.3.45.0/24 (to fit inside the VPC)
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| − | ** Edit subnet, enable auto-assign public IPv4 addresses
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| − | ** Internet Gateway: Create ops345-internet-gateway, attach to vpc-ops345
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| − | ** Create new Route table ops345-route-table, add route for 0.0.0.0/0 through ops345-internet-gateway. Then add explicit subnet association to subnet-ops345
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| − | * Create a new security group "ops345sg" in vpc-ops345 with only the SSH port open.
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| − | * Create a new VM named "router", in the new vpc/subnet.
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| − | ** Follow the instructions in lab 1, except use the subnet-ops345 and ops345sg. Also create a new key called ops345-allmachines-key
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| − | ** Note that "Auto-assign Public IP" is enabled by default, but don't change it.
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| − | ** Wait till it starts, then go to "Elastic IPs" and associate elastic IP with router
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| − | ** In AWS console go to the router/Networking, click on the network interface once, name it router-nic. Then click it, Manage IP addresses, add 10.3.45.10 (first 4 addresses on AWS subnet are not usable). This change requires a reboot.
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| − | = Firewalls =
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| − | | |
| − | * The purpose of a firewall on a server on the internet
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| − | * AWS Security Groups and iptables
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| − | | |
| − | = iptables setup =
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| − | | |
| − | * Install iptables-services, then enable and start the service (same as you did in OPS245).
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| − | * iptables fundamentals
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| − | * Securing services that need to be publicly accessible
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| − | | |
| − | = Port forwarding SSH =
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| − | | |
| − | * Create another VM the same way as "router" but without the elastic IP. Call it www. Name the network interface www-nic and set a secondary private IP to 10.3.45.11
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| − | ** We won't set it up as a web server in this lab, we just need something to forward SSH requests to.
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| − | * firewall:
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| − | ** iptables diagram source: https://documentation.suse.com/sles/15-SP1/html/SLES-all/cha-security-firewall.html
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| − | ** forward incoming tcp port 2211 packets to port 22 on www <source>iptables -t nat -A PREROUTING -p tcp --dport 2211 -j DNAT --to 10.3.45.11:22</source>
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| − | ** allow forwarding to www (or just remove default reject rule)<source>iptables -I FORWARD -p tcp --dport 22 -d 10.3.45.11 -j ACCEPT</source>
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| − | ** don't recheck existing forwarded connections, including replies to accepted traffic <source>iptables -I FORWARD -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT</source>
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| − | ** perform ip masquerading <source>iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE</source>
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| − | ** trubleshooting <source>iptables -I FORWARD -j LOG
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| − | tail -f /var/log/messages </source>
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| − | ** resulting firewall looks like this:<source># iptables -L -n
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| − | Chain INPUT (policy ACCEPT)
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| − | target prot opt source destination
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| − | ACCEPT all -- 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED
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| − | ACCEPT icmp -- 0.0.0.0/0 0.0.0.0/0
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| − | ACCEPT all -- 0.0.0.0/0 0.0.0.0/0
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| − | ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 state NEW tcp dpt:22
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| − | REJECT all -- 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited
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| − | | |
| − | Chain FORWARD (policy ACCEPT)
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| − | target prot opt source destination
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| − | ACCEPT all -- 0.0.0.0/0 0.0.0.0/0 ctstate RELATED,ESTABLISHED
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| − | ACCEPT tcp -- 0.0.0.0/0 10.3.45.11 tcp dpt:22
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| − | REJECT all -- 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited
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| − | | |
| − | Chain OUTPUT (policy ACCEPT)
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| − | target prot opt source destination
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| − | | |
| − | # iptables -t nat -L -n
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| − | Chain PREROUTING (policy ACCEPT)
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| − | target prot opt source destination
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| − | DNAT tcp -- 0.0.0.0/0 0.0.0.0/0 tcp dpt:2211 to:10.3.45.11:22
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| − | | |
| − | Chain INPUT (policy ACCEPT)
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| − | target prot opt source destination
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| − | | |
| − | Chain OUTPUT (policy ACCEPT)
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| − | target prot opt source destination
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| − | | |
| − | Chain POSTROUTING (policy ACCEPT)
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| − | target prot opt source destination
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| − | MASQUERADE all -- 0.0.0.0/0 0.0.0.0/0
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| − | </source>
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| − | * kernel: <source>vi /etc/sysctl.conf # add to the end: net.ipv4.ip_forward = 1
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| − | sysctl -p
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| − | cat /proc/sys/net/ipv4/ip_forward</source>
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| − | * test: <source>tcpdump -n -i eth0 port 2211</source>
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| − | * aws:
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| − | ** allow access to port 2211 in security group
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| − | ** disable source/dest check for router in aws console
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| − | | |
| − | ~. will break out of locked up ssh session
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