F5

From Network Security Wiki


Configuration

Interfaces
  • Control Plane
eth0 - Mgmt
Syslog traffic uses this interface
  • Data Plane
tmm interfaces - usually trunk
HSL - High Speed Logging uses this interface

- Self IP -> Monitoring Traffic
- Float IP -> Application traffic
           -> Only active on Active Unit
           -> Pcaps filter with this IP else it will have Monitoring traffic as well.
Change Hostname
tmsh
modify /sys global-settings hostname bigip1.example.net
save /sys config

F5 Training

LTM How BIG IP process Traffic
  • Node - represent the Ip address
  • Pool member - combination of Ip address and port number, in other words pool member is application server on which F5 will redirect the traffic Pool-combination of pool member.
  • Virtual server - combination of virtual IP and port, is also known as listener and we associate virtual server to pool members.

Loadbalancing Methods

  • Static - Round robin, Ratio
  • Dynamic -LFOPD -> Least connection, Fastest, Observed, Predictive, Dynamic ratio
Details
  • Least connection - Load balancing is based on no of connection counts, if the connection counts are equal it will use round robin.
  • Fastest - No of layer 7 request pending on each member.
  • Observed - ration load balancing method but ratio assigned by BIG IP, No off least connections counts BIG IP assign the request and check dynamically and assign the ratio's of the request.
  • Predictive - similar to observed but assigns the ratio aggressively based on average connection counts .
Load balancing by pool member or node
  • Priority activation -helps to configure back sets for existing pool members .BIG IP will use high priority pool member first .
  • Fallback host is only used for HTTP request ,if all the pool members are not available BIG will redirect the client request

Monitors

  • Check the status of nodes and pool members, if any pool member response time is not good or is not responding Big IP will not send the request to that node.
Monitor type
  • Address check - BIG IP send ICMP request and wait for reply if there is no reply it considers nei down does not send the traffic further to that node.
  • Service check - will check TCP port number on which server is listening ,if no response it considers down ----
  • Content check - we can check if the server is responding with right contest ,like for http request get/http .... request is send .
  • Interactive check - TEST for FTP connection .once connection is open username and password is send then request is send get /file once file is received connection is closed .
  • F5 recommends time out = 3n+1 (frequency) for setting the monitor for http
  • Customization of monitor
  • Assign nodes to monitor


Profiles

  • Defining traffic behavior for virtual server.
  • Profiles contains setting how to process traffic though virtual servers. If for certain application BIG IP load balance the traffic then it will break the client connection

to avoid this we use prescience profile so that return request for the client is send to same server.

  • Persistence profile - is configured for clients and group of clients how BIG IP knows the returning client request need to send to same server, persistence profile is configured taking source IP address of http cookie.
  • SSL termination
  • FTP profile
  • All virtual servers have layer four profile includes TCP, UDP, Fast, l4
  • Profile types - service profile, persistence profile, protocol profile, SSL profile, authentication profile, other profiles.

Persistence Types

  • Source address persistence: keeps the track of source IP address, administrator can set the net mask in persistence record so that all clients in same mask will assigned to same pool member.
  • Limitation - if the client address being NAt'ed.
  • Cookie persistence - only uses http protocol
  • Three modes : (insert ,rewrite ,passive ) mode.
Insert mode - BIG ip create special cookie in HTTP response to client .
rewrite - pool member created blanK cookie and big ip inserts special cookie 
passive - pool member created special cookie and BIG IP let it pass through

SSL Profile

  • SSL is secured socket layer .
  • Website which uses HTTPS we need to us SSL profile as traffic is being Nated for source clients and web app is using https protocol.
  • Using SSL termination BIG can decrypt the traffic and assigned to pool member.
  • BIG IP contains SSL encryption hardware so all the encruption and key exchange are done in hardware .centralized certifiacte management.


iRule

  • iRule is a script that direct traffic though BIG IP , based on TCL command language.
  • iRule give control of inbound and outbound traffic from Big IP.
  • iRule contains following events -> Irule name, events, condition, action

Deploy F5 in KVM

  • Topology
      [client]-------------------------[ F5 ]------------------------[server]
    192.168.45.121         192.168.45.21  |  192.168.68.15          192.168.68.108
                                          |
                                    192.168.122.217
                                          |
                                          |
                                  {10.157.146.116}
                                         Host
  • Download the Image from F5 Portal:
sudo mv BIGIP-16.1.3-0.0.12.qcow2 /var/lib/libvirt/images/
  • Create 3 virtual bridge interfaces:
virbr0 (Ignore if already existing)
vim virbr0.xml

Add bridge details to the file: 

<network>
  <name>virbr0</name>
  <forward mode='nat'>
    <nat>
      <port start='1024' end='65535'/>
    </nat>
  </forward>
  <bridge name='virbr0' stp='on' delay='0'/>
  <ip address='192.168.30.1' netmask='255.255.255.0'>
    <dhcp>
      <range start='192.168.30.50' end='192.168.30.200'/>
    </dhcp>
  </ip>
</network>

sudo virsh net-define virbr0.xml
sudo virsh net-start virbr0
sudo virsh net-autostart virbr0
sudo virsh net-list --all
ip addr show dev virbr0
virbr1
vim virbr1.xml

Add bridge details to the file: 

<network>
  <name>virbr1</name>
  <forward mode='nat'>
    <nat>
      <port start='1024' end='65535'/>
    </nat>
  </forward>
  <bridge name='virbr1' stp='on' delay='0'/>
  <ip address='192.168.45.1' netmask='255.255.255.0'>
    <dhcp>
      <range start='192.168.45.50' end='192.168.45.200'/>
    </dhcp>
  </ip>
</network>

sudo virsh net-define virbr1.xml
sudo virsh net-start virbr1
sudo virsh net-autostart virbr1
sudo virsh net-list --all
ip addr show dev virbr1
virbr2
vim virbr2.xml

Add bridge details to the file: 

<network>
  <name>virbr2</name>
  <forward mode='nat'>
    <nat>
      <port start='1024' end='65535'/>
    </nat>
  </forward>
  <bridge name='virbr2' stp='on' delay='0'/>
  <ip address='192.168.68.1' netmask='255.255.255.0'>
    <dhcp>
      <range start='192.168.68.50' end='192.168.68.200'/>
    </dhcp>
  </ip>
</network>

sudo virsh net-define virbr2.xml
sudo virsh net-start virbr2
sudo virsh net-autostart virbr2
sudo virsh net-list --all
ip addr show dev virbr2


  • Install F5 VM:
sudo virt-install \
--name=bigip \
--description="BIG-IP Local Traffic Manager (LTM) Virtual Edition (VE)" \
--disk path=/var/lib/libvirt/images/BIGIP-16.1.4.3-0.0.3.qcow2,bus=virtio,format=qcow2 \
--disk path=/var/lib/libvirt/images/BIGIP-16.1.4.3-0.0.3.DATASTOR.ALL.qcow2,size=8,bus=virtio,format=qcow2 \
--network=bridge=virbr0,model=virtio \
--network=bridge=virbr1,model=virtio \
--network=bridge=virbr2,model=virtio \
--graphics vnc,password=admin123,listen=0.0.0.0,port=5902 \
--console pty,target_type=serial \
--vcpus=2 --cpu host --ram=8096 \
--os-type=linux --os-variant=rhel6.0 \
--import --autostart --noautoconsole
  • VM Operations and information:
sudo virsh shutdown bigip
sudo virsh destroy bigip
sudo virsh undefine --domain bigip

sudo virsh list --all
sudo virsh net-dhcp-leases default
  • Obtaining Console access:
sudo virsh console bigip
  • Default CLI Credentials:
root / default
  • Set WebUI Credentials using below command:
passwd admin
  • Iptables enable Web UI access using NAT from Host VM:
sudo iptables -t nat -I PREROUTING -p tcp -d 10.157.146.116 --dport 8443 -j DNAT --to-destination 192.168.122.217:443
sudo iptables -I FORWARD -m state -d 192.168.122.0/24 --state NEW,RELATED,ESTABLISHED -j ACCEPT
  • The above rules might not survive reboot of host, hardcoding them:
sudo yum install iptables-services
sudo systemctl start iptables
sudo systemctl enable iptables
sudo service iptables save
  • Apply License
tmsh install /sys license registration-key <KEY>
  • Save Config
tmsh save /sys config
  • Increase bash Columns
vi /root/.bashrc

#!/bin/bash -i
# .bashrc

# User specific aliases and functions

alias rm='rm -i'
alias cp='cp -i'
alias mv='mv -i'

# Source global definitions
if [ -f /etc/bashrc ]; then
        . /etc/bashrc
fi
resize() {

  old=$(stty -g)
  stty raw -echo min 0 time 5

  printf '\033[18t' > /dev/tty
  IFS=';t' read -r _ rows cols _ < /dev/tty
  stty "$old"
  stty cols $cols
  stty rows $rows
  export COLUMNS=$cols
  export LINES=$rows
}
[[ $(tty) = '/dev/ttyS0' ]] && stty cols 1000



stty -F /dev/ttyS0 rows 100
stty -F /dev/ttyS0 cols 100


Prepare the Ubuntu Minimal Image

  • Download Image file:
virt-builder --list
virt-builder centos-7.5 --format qcow2 --size 20G -o centos75-client.qcow2 --root-password password       # no root password set
sudo mv centos75-client.qcow2 /var/lib/libvirt/images/
sudo cp /var/lib/libvirt/images/centos75-client.qcow2 /var/lib/libvirt/images/centos75-server.qcow2

Install Client

  • Start VM:
sudo virt-install \
--name=client \
--description="Ubuntu Minimal Client" \
--disk path=/var/lib/libvirt/images/centos75-client.qcow2,bus=virtio,format=qcow2 \
--network=bridge=virbr1,model=virtio \
--graphics none \
--console pty,target_type=serial \
--vcpus=1 --cpu host --ram=1024 \
--os-type=linux \
--os-variant=rhel6.0 \
--import --autostart --noautoconsole
  • Obtaining Console access:
sudo virsh console client
  • Basic config:
sudo vi /etc/hostname        # change hostname

sudo yum install httpd
sudo systemctl enable httpd
sudo systemctl start httpd
sudo systemctl status httpd

sudo iptables -F

Install WebServer

  • Start VM:
sudo virt-install \
--name=server \
--description="CentOS WebServer" \
--disk path=/var/lib/libvirt/images/centos75-server.qcow2,bus=virtio,format=qcow2 \
--network=bridge=virbr2,model=virtio \
--graphics none \
--console pty,target_type=serial \
--vcpus=1 --cpu host --ram=1024 \
--os-type=linux \
--os-variant=rhel6.0 \
--import --autostart --noautoconsole
  • Obtaining Console access:
sudo virsh console server
sudo iptables -F

F5 Configuration

Create VLAN

net vlan myVlan {
    fwd-mode l3
    if-index 128
    interfaces {
        1.2 { }
    }
    sflow {
        poll-interval-global no
        sampling-rate-global no
    }
    tag 4094
}

Create SelfIP

net self SelfIpforPool {
    address 192.168.68.15/24
    traffic-group traffic-group-local-only
    vlan myVlan
}

Create Pool

ltm pool myPool {
    members {
        server1:http {
            address 192.168.68.108
            logging enabled
            session monitor-enabled
            state up
        }
    }
    monitor http
}

Create VS

ltm snat-translation 192.168.68.7 {
    address 192.168.68.7
    inherited-traffic-group true
    traffic-group traffic-group-1
}
ltm snatpool mySNatIP {
    members {
        192.168.68.7
    }
}

ltm virtual myVS {
    creation-time 2024-04-30:09:50:10
    destination 192.168.45.21:http
    ip-protocol tcp
    last-modified-time 2024-05-01:02:29:35
    mask 255.255.255.255
    pool myPool
    profiles {
        tcp { }
    }
    serverssl-use-sni disabled
    source 0.0.0.0/0
    source-address-translation {
        pool mySNatIP
        type snat
    }
    translate-address enabled
    translate-port enabled
    vlans {
        ExternalVlan
    }
    vlans-enabled
    vs-index 2
}

Enable Internet Access on VMs

On VMs
  • Add Interface for the common network on host to the VMs:
sudo virsh attach-interface --type bridge --source virbr0 --model virtio client
On Host
sudo sysctl -w net.ipv4.ip_forward=1
sudo iptables --table nat --append POSTROUTING --out-interface ens192 -j MASQUERADE      # ens192  is default exit interface in Host
sudo iptables --insert FORWARD --in-interface virbr0 -j ACCEPT                           # virbr0 is newly added interface in VM



References





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