Archive for March 4th, 2010

T-23 | Bootcamp Day 1 review

Hello all!
I’m really excited! ‘coz i’m finally doing the bootcamps that i purchased a couple of months back :) . I started the bootcamp yesterday and i went through Day 1 and i took notes on WAVE.I must say, i was pleasantly surprised by the content covered on the first day. I expected it to be very basic, but Marvin did dive into some advanced stuff ( but no configuration :( ).

Here are the notes and i hope you find them useful :

ASA

  • Make sure you don’t block traffic flows as we configure tasks ( don’t screw up earlier tasks )
  • Marvin’s of the opinion that it’ll mostly be 8.0 running on the ASA on the lab
  • It’s a good idea to read through the lab once before we start configuring ( helpful in changing firewall modes, contexts ,etc )
  • Add a “description” on the catalysts if necessary ( to identify the interfaces connected to the switch ). Make this a habit. ( helps )
  • Redundant interfaces
    • Multiple interfaces grouped together
    • order of configuration determines preference
  • We can use both Subinterfaces and the real interface on the ASA. In case of the sub-interfaces ( e 0/1.100 VLAN 100 ), the ASA would send the packets with a dot1q tag on, in case of the interface with the actual interface ( ex : e 0/1 ), it would send it untagged.
    • So we have to program the switch to accept untagged packets in the trunk link. This can be done using native-vlans.
  • Addresses, protocols and ports can be found under the “references section” of any Configuration guide for 8.X . This is cool!
  • Draw out network flows for protocols running in the network to visualize what needs to be allowed.
  • Routing protocols
    • ASA supports the following routing protocols :
      • static
      • Rip v1/v2
      • OSPF
      • EIGRP
    • Different OSPF areas in a firewall, can be configured under a signle process or multiple processes
    • Configuring them under one process will alow routing information to pass from one OSPF area to the other freely
    • configuring them as 2 separate processes, will logically isolate the areas. To exchange routes, we need to explicitly redistribute.
    • So be careful when you configure them under 1/separate OSPF processes.
    • Having an exact OSPF match, can be a good thing to check if we have configured the addresses correctly.
  • NAT
    • Nat 0 -> Nat exemption
    • Options in NAT configuration
      • TCP/UDP maximum connection limits
      • TCP Half-open connections
      • DNS rewrite
      • Disable randomizing sequence numbers
    • By default, NAT-control is disabled.
    • NAT-control only applies for traffic between 2 interfaces of “different” security levels.
  • In transparent firewall, TCP , UDP traffic is inspected by default
  • “allocate-interface redundant1.3 int1
  • There are sample ASA configurations under the “references”section in the ASA configuration guides! -> AWESOME!
  • Good practice is to save the config in a notepad file before we start Failover configuration.

IOS F/w

  • The log-input command in ACL logging , logs the following info
    • list name/number
    • permit/deny
    • protocol name/number
    • source/destination IP
    • port numbers
    • MAC addresses
    • Input VC
  • The first 5 are also logged when you do the “log” option instead of log-input
  • The routing protocols use a “distribute-list” to filter routes
  • The autocommand for Dynamic ACL’s configured on the LINE VTY 0 4 lines, blocks also legitimate management traffic
  • By using the “host” keyword, the “any” in the source address portion of the ACL is replaced by the host that underwent the authentication.
  • Thing to remember is “reflexive” ACL’s don’t wory for locally generated trarffic
  • So we need to statically permit required traffic back in
  • or configure local policy-routing
  • we can use the “router-traffic” keyword in the CBAC inspect commands, to inspect locally generated traffic

I’m going to be starting Day 2 of the bootcamp in about 30 mins . Surf with me on the WAVE :)

Cheers,

TacACK

BOOTCAMP – DAY 1

Here we go! :) I’m not a fan of the INE bootcamp, but just ‘coz i’ve paid for it, i’m gonna give it a good once over!

ASA

  • Make sure you don’t block traffic flows as we configure tasks ( don’t screw up earlier tasks )
  • Marvin’s of the opinion that it’ll mostly be 8.0 running on the ASA on the lab
  • It’s a good idea to read through the lab once before we start configuring ( helpful in changing firewall modes, contexts ,etc )
  • Add a “description” on the catalysts if necessary ( to identify the interfaces connected to the switch ). Make this a habit. ( helps )
  • Redundant interfaces
  • Multiple interfaces grouped together
  • order of configuration determines preference
  • We can use both Subinterfaces and the real interface on the ASA. In case of the sub-interfaces ( e 0/1.100 VLAN 100 ), the ASA would send the packets with a dot1q tag on, in case of the interface with the actual interface ( ex : e 0/1 ), it would send it untagged.
  • So we have to program the switch to accept untagged packets in the trunk link. This can be done using native-vlans.
  • Addresses, protocols and ports can be found under the “references section” of any Configuration guide for 8.X . This is cool!
  • Draw out network flows for protocols running in the network to visualize what needs to be allowed.
  • Routing protocols
  • ASA supports the following routing protocols :
  • static
  • Rip v1/v2
  • OSPF
  • EIGRP
  • Different OSPF areas in a firewall, can be configured under a signle process or multiple processes
  • Configuring them under one process will alow routing information to pass from one OSPF area to the other freely
  • configuring them as 2 separate processes, will logically isolate the areas. To exchange routes, we need to explicitly redistribute.
  • So be careful when you configure them under 1/separate OSPF processes.
  • Having an exact OSPF match, can be a good thing to check if we have configured the addresses correctly.
  • NAT
  • Nat 0 -> Nat exemption
  • Options in NAT configuration
  • TCP/UDP maximum connection limits
  • TCP Half-open connections
  • DNS rewrite
  • Disable randomizing sequence numbers
  • By default, NAT-control is disabled.
  • NAT-control only applies for traffic between 2 interfaces of “different” security levels.
  • In transparent firewall, TCP , UDP traffic is inspected by default
  • allocate-interface redundant1.3 int1 (alias)
  • There are sample ASA configurations under the “references”section in the ASA configuration guides! -> AWESOME!
  • Good practice is to save the config in a notepad file before we start Failover configuration.

IOS F/w

  • the log-input command in ACL logging gets the following info
  • list name/number
  • permit/deny
  • protocol name/number
  • source/destination IP
  • port numbers
  • MAC addresses
  • Input VC
  • The first 5 are also logged when you do the “log” option instead of log-input
  • The routing protocols use a “distribute-list” to filter routes
  • The autocommand for Dynamic ACL’s configured on the LINE VTY 0 4 lines, blocks also legitimate management traffic
  • The “host” keyword, the “any” in the source address portion of the ACL is replaced by the host that did the authentication
  • Thing to remember is “reflexive” ACL’s don’t wory for locally generated trarffic
  • So we need to statically permit required traffic back in
  • or configure local policy-routing
  • we can use the “router-traffic” keyword in the CBAC inspect commands, to inspect locally generated traffic

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