Archive for the 'Uncategorized' Category

I am trying to connect a BGP session between a Juniper JunOS device and a Cisco device.

I started with a very basic ipv4 config on the JunOS device, but had a more more complicated BGP config on the Cisco side ( vpnv4 and mdt ).

As soon as I brought the connection up the Cisco router started to complain

*Jan 14 17:27:00.597: %BGP-3-NOTIFICATION: sent to neighbor 192.168.1.1 2/7 (unsupported/disjoint capability) 0 bytes  FFFF FFFF FFFF FFFF FFFF FFFF FFFF FFFF 003B 0104 FC00 005A 0A01 1205 1E02 0601 0400 0100 0102 0280 0002 0202 0002 0440 0200 7802 0641 0400 00FC 00

It appears there is a hidden command, to stop the routers negotiating capabilities, but that just seems wrong. What I actually needed was to match up the Juniper side with the Cisco side. In this case, I added the following family statements to the BGP config

set protocol bgp {
    family inet-vpn {
        unicast;
    }
    family inet-mdt {
        signaling;
    }
}

Now the BGP session comes up just fine.

Cheers
Pete

Our external routers run full routes, but on the internal network the routers don’t have sufficient memory, nor do they need full routes.

To ensure that someone does not blow them up be accidently advertising full routes into the internal network, we filter the routes they will accept.

To do this, we configure a distribution-list on the router we are trying to protect.

lets say our block of address space is 170.12.42.0/23

ip prefix-list AS1234-filter seq 5 permit 170.12.42.0/23 le 32
ip prefix-list AS1234-filter seq 10 permit 0.0.0.0/0

then we add this to the OSPF router process

router ospf 1
 router-id 192.168.1.1
 log-adjacency-changes
 distribute-list prefix AS1234-filter in

Now you should only see the routes you need ( and the default router in this example ) in your router process

Cheers
Pete

I was looking for the remote browsers ip’s in a rails application today, and created the following method in my controller.

  def remote_ip
    IPAddress.parse ( request.remote_ip )
  end

The idea was simply to be create a NetAddr object from the ip address so that it could be manipulated in the view.

The code does not work, because with ipv6 the remote_ip returns returns

0:0:0:0:0:0:0:1%0

and NetAddr does not appear to like the % syntax. I tried the same request from a remote computer to try and work out the syntax it was giving me, and to try and work out the relevance of the number after the %, and got

2001:7a3:ee23:2:20c:29ff:fe19:8878%0

I can’t bring myself to just cut this information off without knowing what it means, so eventually I found RFC 4007 which is titled ‘IPv6 Scoped Address Architecture’. If you read section 11 you will see that the % syntax refers to the zone id which is the interface on the source host. I understand the point of this, but for the sake of getting the remote ipv6 address in my rails application, I probably don’t need it. To create the IPAddress object, I just need to use the address preceding the %. This seems to suffice

def remote_ip
    IPAddress.parse ( request.remote_ip.split("%").first )
end

Which when I look at the page gives me

2001:7a3:ee23:2:20c:29ff:fe19:8878

Which will do just fine

Cheers
Pete

I setup a couple of mac mini’s at work to run the various monitoring screens. For a while we have used a little piece of java script to switch between browser tabs, but its a bit limited, and there are a few monitoring tools we have that are not web based and only run on windows.

Using Virtual Box I setup a couple of windows machines, and then for each tool I wanted to display, I created a space and made a virtual machine full screen to run the tool.

At the moment, I have 3 browsers on 3 spaces, and then two virtual machines on an additional 2 spaces. Now I need to turn it into a slide show.

I created a little AppleScript script to switch the screens. Its rather crude in that it sends key codes to the system events application and, I can’t seem to get the application to exit gracefully when I do file->quit.

Here is the script

(* 
 
Title: Spaces slide show
 
list of apple key codes is a available here:
http://lists.apple.com/archives/Applescript-users/2004/Apr/msg00076.html
 
*)
 
(* Don't set switch_delay to less that 2, you might lock up your machine whilst it madly switches between spaces *)
set switch_delay to 5
 
repeat
	tell application "System Events"
		key code 124 using {control down}
		delay switch_delay
	end tell
end repeat

update 1: I had one issue where the screen switching would stop when it got to a screen that was running virtual box. If you go to Virtual box settings, there is an option to automatically capture the keyboard, this needs to be disabled to make it work.

update 2: The swish effect becomes quite annoying quite quickly.

defaults write com.apple.dock workspaces-swoosh-animation-off -bool YES
killall Dock

This seems to do the trick for now.

Cheers
Pete

Getting files onto a cisco router does not need to be hard

router(config)#ip scp server enable
router(config)#username pete privilege 15 password 0 secret

Then you can simply SCP the file

host123:Downloads pete$ scp anyconnect-macosx-i386-2.5.1025-k9.dmg pete@router:anyconnect-macosx-i386-2.5.1025-k9.pkg
Password:
anyconnect-macosx-i386-2.5.1025-k9.pkg                                                                   100% 4560KB 106.1KB/s   00:43
host123:Downloads pete$

Cheers
Pete

Update: It appears on IOS later than 12.4(24)T3, you need to also configure AAA for this to work, otherwise you get a “Permission denied” error when you try and SCP the file.

aaa new-model
aaa authentication login default local
aaa authorization exec default local