Ubuntu – Managing Cisco Devices via Serial / Rollover Cable

KB ID 0000400 

Problem

A while back I ran though “Managing Cisco ASA devices via the ASDM with Ubuntu“, I prefer to work at command line, with a new firewall my only choice is via the console port, In a windows environment I can fire up Hyperterminal and I’m away. With Linux there a couple of things to do first.

Solution

Step 1 (Get the Serial / RS232 / COM Port working)

As pictured above, this is being done on my Acer Netbook so I don’t have a serial port. I need to use a USB to Serial converter, If your machine has a serial port then simply skip this section.

1. Plug in your serial converter and wait a few seconds, open a terminal window (Applications > Accessories > Terminal) and issue the following command,

[box]dmesg[/box]

2. Amazingly it looks like been installed with the correct driver, without any effort by me at all! Lets make sure, unplug the USB to serial converter then issue the following command,

[box]lusb[/box]

Then plug the device back in and run the same command, notice the serial port has popped onto the list.

Note: If you not as lucky as me follow the excellent advice here to install the drivers you need.

Step 2 Install and Configure Minicom

1. Open a terminal window and issue the following command,

[box]sudo apt-get install minicom[/box]

Tap in your password, then enter “Y” for yes when prompted.

4. We need to know the connection name for the USB to Serial converter, issue the following command (See mines called ttyUSB0).

[box]dmesg | grep tty[/box]

5. Now lets fire up Minicom with the following command,

[box]sudo minicom[/box]

Tap in your password again, then as requested press CTRL+A, then Z.

6. To configure the serial settings press O (that’s O for Oscar not zero).

7. Select “Serial Port Setup”.

8. Press A to set the device.

9. As we discovered (above) ours is called ttyUSB0, so change the device to /dev/ttyUSB0.

10. Press C to change the connection speed to 9600 baud, Press Q (to set 8 bits, no stop bit, and 1 parity bit. On mine this was set by default), press {enter} to exit.

11. Press F to turn off hardware flow control (Some posts will say leave it on, I generally turn if off and I’ve never seen anything break!). Press G to disable software flow control (if enabled).

12. Then Select “Save setup as..”, and give is a sensible name. (If you went back too far simply press O again to get back here).

13. Now the settings are saved you can launch them at anytime with,

[box]sudo minicom {filename}[/box]

Note: Sometimes your serial drive gets locked up but a reboot will solve the problem.

14. Here’s me connected to an ancient old catalyst switch.

15. And the baby PIX on my test network.

Note: If your keystrokes are not getting sent: From the main menu (CTRL+A then Z) Press E to turn on local echo.

 

Related Articles, References, Credits, or External Links

NA

Cisco CSC Module Error – Activation Warning

KB ID 0000392 

Problem

You try to connect to your Cisco CSC module, and see the following error.

Error: Activation Warning CSC is not activated. Please run setup wizard under Configuration > Trend Micro Content Security > CSC Setup > Wizard Setup to perform setup process. Click OK button to to to Trend Micro Content Security Setup wizard.

Naturally if you’ve never setup the CSC you are going to see this, but what if it suddenly starts doing this?

Solution

1. Connect to the ASA that the CSC module is in.

2. Issue the following command,

[box]sh modu 1 det[/box]

3. This ones unresponsive, it probably just need restarting, to do that issue the following command.

[box]hw-module module 1 reset[/box]

4. They can take a little while to come up (apply the cup of coffee rule). Then to see if it’s back up again use the same command you used earlier.

[box]sh mod 1 det[/box]

That didn’t work! Sometimes CSC modules do fail!, I had one client go through three in a year, If doing the above or running through the setup wizard (you did write down the licence numbers that came with the CSC didn’t you?) doesn’t work then you need to log a call to TAC.

 

Related Articles, References, Credits, or External Links

Cisco CSC Module stop it scanning its own update traffic

Cisco ASA – Changing VPN IP Addresses

KB ID 0000391

Problem

I had a client the other week with about 25 sites, his core site was changing ISP and therefore changing its IP address. On the main site this is pretty straightforward, just change the outside interfaces IP address, sub net mask and the default route (That’s the default gateway for non cisco-ites).

All well and good, but what about his other 24 sites? They all had VPN’s back to the main site, and all these VPN’s were “hairpinned” together for “spoke to spoke” communication.

Well you can simply delete the VPNs and recreate them, but multiply that by 24 – then add on all the extra config for the hairpins and that’s a massive amount of work (and for the client a LOT of downtime.) So a swift config change on the remote sites is a much better idea.

For Cisco PIX firewalls running version 6 click here.

Solution

Option 1 From Command Line (for ASDM see below)

In this example my main site (123.123.123.123) has changed its IP address to (234.234.234.234), and I need to reconfigure the remote site(s).

1. First – you need to understand a couple of things, for a VPN to work, it needs the IP address of the “Other End” of the tunnel in two places.

a. In the Cryptomap.
b. In a Tunnel Group.

2. First lets find the cryptomap, connect to the ASA, log in go to enable mode then configuration mode.

[box]

RemoteSite>
RemoteSite> enable
Password: ***********
RemoteSite# configure terminal
RemoteSite(config)#[/box]

3. To see all the cryptomaps issue a “show run crypto map” command. (you may see more or less depending on the amount of VPN tunnels you have.

[box]

RemoteSite(config)# show run crypto map
crypto map outside_map 1 match address outside_1_cryptomap
crypto map outside_map 1 set pfs
crypto map outside_map 1 set peer 111.111.111.111
crypto map outside_map 1 set transform-set ESP-3DES-SHA
crypto map outside_map 2 match address outside_2_cryptomap
crypto map outside_map 2 set pfs
crypto map outside_map 2 set peer 123.123.123.123 <<<< Here it is!!!
crypto map outside_map 2 set transform-set ESP-3DES-SHA
crypto map outside_map 3 match address outside_3_cryptomap
crypto map outside_map 3 set pfs
crypto map outside_map 3 set peer 133.133.133.133
crypto map outside_map 3 set transform-set ESP-3DES-SHA
crypto map outside_map 4 match address outside_4_cryptomap
crypto map outside_map 4 set pfs
crypto map outside_map 4 set peer 144.144.144.144
crypto map outside_map 4 set transform-set ESP-3DES-SHA
RemoteSite(config)#[/box]

4. From the example above we can see the tunnel we want to change is using “outside_map 2” so lets remove the entry for the old IP address and put one in for the new IP address.

[box]

RemoteSite(config)# no crypto map outside_map 2 set peer 123.123.123.123
WARNING: The crypto map entry will be incomplete!
RemoteSite(config)# crypto map outside_map 2 set peer 234.234.234.234
RemoteSite(config)#[/box]

5. That’s the cryptomap changed, now for the tunnel group. You can see all your tunnel groups with a “sho run tun” command.

[box]

RemoteSite(config)# sho run tun
tunnel-group DefaultL2LGroup ipsec-attributes
isakmp keepalive threshold 20 retry 2
tunnel-group DefaultRAGroup ipsec-attributes
isakmp keepalive threshold 20 retry 2
tunnel-group DefaultWEBVPNGroup ipsec-attributes
isakmp keepalive threshold 20 retry 2
tunnel-group 111.111.111.111 type ipsec-l2l
tunnel-group 111.111.111.111 ipsec-attributes
pre-shared-key *****
tunnel-group 123.123.123.123 type ipsec-l2l <<<< Here it is!!!
tunnel-group 123.123.123.123 ipsec-attributes
pre-shared-key *****
tunnel-group 133.133.133.133 type ipsec-l2l
tunnel-group 133.133.133.133 ipsec-attributes
pre-shared-key *****
isakmp keepalive threshold 20 retry 2
tunnel-group 144.144.144.144 type ipsec-l2l
tunnel-group 144.144.144.144 ipsec-attributes
pre-shared-key *****[/box]

6. To delete a tunnel group, you use the “clear config tunnel-group” command.

Note: Before you delete it, make sure you know the pre shared key / shared secret – to see this, issue a “more system:running-config” command.

[box]

RemoteSite(config)# clear config tunnel-group 123.123.123.123
RemoteSite(config)#[/box]

7. Then simply create a new tunnel group, with the new IP address, and the same shared secret / pre shared key as the old one.

[box]

RemoteSite(config)# tunnel-group 234.234.234.234 type ipsec-l2l
RemoteSite(config)# tunnel-group 234.234.234.234 ipsec-attributes
RemoteSite(config-tunnel-ipsec)# pre-shared-key 123456789
[/box]

8. Save the new config with a “write mem” command

[box]

RemoteSite(config)# write mem

Building configuration...

Cryptochecksum: f3645705 ae6bafda c5606697 ecd61948
9830 bytes copied in 1.550 secs (9830 bytes/sec)
[OK]
RemoteSite(config)#

[/box]

9. Job done!

Well that didn’t seem very quick? No, but for the sake of explanation I did go a little deep, if you have multiple sites, just have the following in notepad.

configure terminal
no crypto map outside_map 2 set peer 123.123.123.123
crypto map outside_map 2 set peer 234.234.234.234
clear config tunnel-group 123.123.123.123
tunnel-group 234.234.234.234 type ipsec-l2l
tunnel-group 234.234.234.234 ipsec-attributes
pre-shared-key 123456789
write mem

Then simply jump from site to site changing the cryptomap name and shared secret for each one. If you get all this info first, you can migrate hundreds of sites in minutes, (That’s why I prefer command line to GUI ASDM).

Option 2 From ASDM

1. Connect to the ASDM, Configuration > Site-to-Site VPN > Advanced > Crypto Maps > Select the cryptomap going to 123.123.123.123 > Edit > Add the new IP Address.

2. Remove the old one > OK > Apply.

3. Configuration > Site-to-Site VPN > Advanced > Tunnel Groups > Select the old one > Delete > Apply.

4. Then to add a new one > Add > Set the Tunnel group name to the new IP > Enter the shared secret > OK > Apply.

5. Finally Save the changes > File > Save running configuration to Flash.

Cisco PIX (Version 6)

For older firewalls you will notice there is no “Tunnel-Group”, these came in with version 7. The process is similar, again you have to change the peer entry in the cryptomap, but you also need to set an isakmp peer.

no crypto map outside_map 20 set peer 123.123.123.123
crypto map outside_map 20 set peer 234.234.234.234
no isakmp key ******** address 123.123.123.123 netmask 255.255.255.255
isakmp key 123456789 address 234.234.234.234 netmask 255.255.255.255

 

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