Wednesday, August 21, 2013

Cisco WS-X4013+TS ROMMON Upgrade

I recommissioned a Cisco 4503 switch today with a SUP II+TS and whenever I get the chance to wipe a switch or device and start fresh I like to upgrade the IOS and ROMMON if applicable. This procedure was slightly different from a Router ROMMON upgrade:
   
   ! Copy the ROMMON image to the bootflash:
   Switch#copy ftp://192.168.1.1/cat4500-ios-promupgrade-122_31r_SGA4 bootflash:cat4500-ios-promupgrade-122_31r_SGA4

   ! Once copied, reload the switch
   Switch#reload

   ! Press Crtl-C to enter ROMMON during bootup and run the following command
   rommon 1 > boot bootflash:cat4500-ios-promupgrade-122_31r_SGA4

After the ROMMON upgrade has completed, the switch wil reload automatically and boot into IOS. You can perform a show version to verify that the ROMMON has been upgraded.

More detailed instruction can be found in the Release Notes of the ROMMON image.

Monday, August 19, 2013

Zone Based Firewall Example, Part 2 - Guest Zone

Zone Based Firewalls (ZBF) are an easy way to turn your Security licensed Cisco ISR G2 Router into a firewall. In this multi-part example, I'll create a 5 zone firewall which will include an Inside, Outside, DMZ, Guest and Self zones. This is a basic example to demonstrate the the structure of a ZBF, not a study in firewall design.

Just to clarify:

DMZ - Your Demilitarized Zone for web servers and FTP servers

Guest - Wireless guest access to outside

Inside - Your inside LAN

Outside - Represents the Internet

Self - This is the router itself, traffic generated by the router and traffic destined to the router, e.g. TACACS+, SSH, Telnet, TFTP, etc.


In Part 2, we'll look at creating a simple guest wireless network which will allow users connected to the Guest wireless to access the Internet, but not the inside LAN.




Define Zone for Zone Based Firewall

Zone security GUEST

! Class-Map that matches criteria specified in the GUEST-TO-OUT-ACL

Class-map type inspect GUEST-TO-OUT-CLASS
 Match access-group name GUEST-TO-OUT-ACL

! Policy-Map to inspect inside traffic going outbound, dropped traffic is logged

Policy-map type inspect GUEST-TO-OUT-POLICY
 Class type inspect GUEST-TO-OUT-CLASS
  Inspect
 Class class-default
  Drop log

! Create Zone Pair and Apply Service-Policy (Policy-Maps)

Zone-pair security GUEST-TO-OUT source GUEST destination OUTSIDE
 Service-policy type inspect GUEST-TO-OUT-POLICY

Assign Zone to router interfaces

Interface GigabitEthernet0/2
 Zone-member security GUEST

! ACL allows GUEST network to access the Internet

ip access-list extended GUEST-TO-OUT-ACL
 permit ip 172.16.0.0 0.0.0.255 any









Cisco IP Phone Firmware Downgrade Issue

During a Cisco 7965G IP Phone install, I noticed that the phone would download the firmware from the Cisco Unified Communications Server (CUCM), but would not actually install the firmware. The 7965 had a newer load, 9.3(1)SR1, and I was attempting to downgrade to 9.2(3) because of the limitation of the Cisco Phone Designer software. After several reboots of the IP Phone and tinkering with the FTP Services on the CUCM, I proceeded to open a TAC case with Cisco to see if they could solve the issue. After three weeks of packet captures, CUCM log dumps, and even video recording the events, we discovered that the 7965 hardware version that I had (v14) only worked with 9.3(1)SR1 and above. This is clearly stated in the Release Notes for 9.3.(1)SR1, so it just goes to show, don't ignore the Release Notes.


Wednesday, March 20, 2013

Zone Based Firewall Example, Part 1 - Inside/Outside Zones

Zone Based Firewalls (ZBF) are an easy way to turn your Security licensed Cisco ISR G2 Router into a firewall. In this multi-part example, I'll create a 5 zone firewall which will include an Inside, Outside, DMZ, Guest and Self zones. This is a basic example to demonstrate the the structure of a ZBF, not a study in firewall design.

Just to clarify:

DMZ - Your Demilitarized Zone for web servers and FTP servers

Guest - Wireless guest access to outside

Inside - Your inside LAN

Outside - Represents the Internet

Self - This is the router itself, traffic generated by the router and traffic destined to the router, e.g. TACACS+, SSH, Telnet, TFTP, etc.


In Part 1, we'll create the foundation of our ZBF, the inside and outside zones which will allow your users to access the Internet and allow ICMP traffic into your LAN.



! Define Zones for Zone Based Firewall

Zone security INSIDE
Zone security OUTSIDE

! Class-Map that matches criteria specified in the IN-TO-OUT-ACL

Class-map type inspect IN-TO-OUT-CLASS
 Match access-group name IN-TO-OUT-ACL

! Class-Map that matches criteria specified in the OUT-TO-IN-ACL

Class-map type inspect OUT-TO-IN-CLASS
 Match access-group name OUT-TO-IN-ACL

! Policy-Map to inspect inside traffic going outbound, dropped traffic is logged

Policy-map type inspect IN-TO-OUT-POLICY
 Class type inspect IN-TO-OUT-CLASS
  Inspect
 Class class-default
  Drop log

! Policy-Map to pass (not inspect) outside traffic coming in, dropped traffic is logged

Policy-map type inspect OUT-TO-IN-POLICY
 Class type inspect OUT-TO-IN-CLASS
  Pass
 Class class-default
  Drop log

! Policy-Map to deny all traffic

Policy-map type inspect DENY-ALL-POLICY
 Class class-default
  Drop log

! Create Zone Pairs and Apply Service-Policies (Policy-Maps)

Zone-pair security IN-TO-OUT source INSIDE destination OUTSIDE
 Service-policy type inspect IN-TO-OUT-POLICY
Zone-pair security OUT-TO-IN source OUTSIDE destination INSIDE
 Service-policy type inspect OUT-TO-IN-POLICY

! Assign Zones to router interfaces

Interface GigabitEthernet0/0
 Zone-member security INSIDE
Interface GigabitEthernet0/1
 Zone-member security OUTSIDE

! ACL allows inside network to access the web and to allow pings to the outside

Ip access-list extended IN-TO-OUT-ACL
 Permit tcp 10.10.1.0 255.255.255.0 any eq www
 Permit icmp 10.10.1.0 255.255.255.0 any echo

! ACL allows pings from the outside to the 10.10.1.0 network

Ip access-list extended OUT-TO-IN-ACL
 Permit icmp any 10.10.1.0 255.255.255.0 unreachable 






Friday, February 15, 2013

Cisco Router ROMMON Upgrade

Besides keeping your IOS code up to date, you may want to also update your router's ROMMON version. The first thing to do is download the ROMMON image from Cisco for you specific router. Once downloaded, you'll need to place it in your TFTP server folder so that it can be downloaded by your router. Next, go to your router and type in the following command:

 Router#upgrade rom-monitor file tftp://192.168.30.10/C2800NM_RM2.srec.124-13r.T11

You should change C2800NM_RM2.srec.124-13r.T11 to the actual file name that you downloaded from Cisco. Execute the command, the router will download the image and prompt you to allow it to reboot.

 Router#upgrade rom-monitor file tftp://192.168.30.10/C2800NM_RM2.srec.124-13r.T11
 Loading C2800NM_RM2.srec.124-13r.T11 from 192.168.30.10 (via GigabitEthernet0/0): !!!!!!!
 [OK - 1626367 bytes]

 This command will result in a  'power-on reset' of the router!
 Continue? [yes/no]: yes

 System configuration has been modified. Save? [yes/no]: no
 ROMMON image upgrade in progress.
 Erasing boot flash  eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee
 Programming boot flash ppppppppppp
            
 Now Reloading

Select Yes and the router will erase the current boot flash and program the new image and reload.