Calin

Author Archives: Calin

F5 BIG-IP Plugin with Firefox 52 workaround

It’s not news anymore that Mozilla is stopping support for NPAPI (Netscape Plugin API). With the release of Firefox 52 version, I believe that only Flash plugin is enabled by default.

I’ll skip the discussion about NPAPI plugins and Mozilla’s decision to stop the support, however the reality is that for me it has a strong impact in certain areas. One of this areas is the F5 BIG-IP, specifically the APM and possibility to launch Application (like RDP) from the Webtop interface.

I’m relying heavily on a F5 BIG-IP VE machine to connect to my home lab when I’m remote. The Webtop functionality gives me the possibility to use only a Browser to connect to my applications at home, keeping me away from any F5 client installation on the machine that I use. Usually this machine is my MacBook or PC, and the F5 client installation should not be a big thing, however I like the clientless option.

The F5 Webtop functionality is possible due to a NPAPI plugin called “F5 Network Host Plugin” which usually installs in the browser when you access the F5 APM. So yes, you still need to install something, but this browser plugin is Continue reading

Draw network diagrams online [2016 Edition]

In this post from 2011 I was explaining that my preferred online tool to draw network diagrams is LucidChart.com. Since then LucidChart.com developed really good and added constantly new features. Unfortunately with the new great additions some not so nice restrictions appeared for the free account.
Those restrictions (like 5 active documents) really make it difficult for me to work with this tool as I got used to a different style.

I’m not a cheap guy! If I would use this tool professionally there would be no problem to buy a subscription package, but at work Visio is saint (unfortunately) and the rest of the time, especially when I’m on my Mac, I just need a fast tool to draw brief network diagrams like for my blog or fast explanation to somebody online.

LucidChart.com is my recommendation if you rely on online tool to work with Visio documents. Last time when I checked their Visio import tool was doing a great job.

Back to this story, I was looking online for another tool when I came across Draw.io.

Draw.io doesn’t need an account creation, rather it just give you direct access to the tool.
Since Continue reading

Cisco ASA packet capture showing bidirectional traffic flow

Recently I had to troubleshoot some communication issues via a Cisco ASA device and the packet capture on the IOS comes in handy for this task.

When you have a lot of traffic over ASA and you’re interested in a particular IP address, the basic packet capture lesson says that you should configure an access-list to limit the captured packets for the interesting traffic only.

Let’s assume that I have a particular interest for the traffic to and from the IP address 10.0.0.10.

I created a standard ACL to match only the traffic related to 10.0.0.10:

access-list TS standard permit host 10.0.0.10

Afterward I attached the created ACL to a packet capture on a particular interface (let’s call it “lan”).

capture TSHOOT access-list TS interface lan

You can find the above lines in almost any how-to regarding packet capture on Cisco ASA.

Checking the capture I noticed that traffic is unidirectional captured:

FW# show capture TSHOOT

4 packets captured

   1: 20:15:32.757010       802.1Q vlan#10 P0 192.168.0.10 > 10.0.0.10: icmp: echo request
   2: 20:15:33.759283       802.1Q vlan#10 P0 192.168.0.10 > 10. Continue reading

IPsec VPN Mikrotik to Linux

After writing the Mikrotik IPsec VPN article and I got some questions about how Mikrotik will work with a Linux device to build an IPsec VPN. I did notice that the questions were more oriented for a copy / paste solution, so I’ll provide one that it’s working. If you need more details about why the solution is like it this, please let me know.
Also don’t forget to customize the solution as you need.

Read more on IPsec VPN Mikrotik to Linux…

New GNS3 1.0 Beta 1

It appears that there are some significant changes ongoing with GNS3:     As mentioned by the GNS3 CEO and co-founder Stephen Guppy on 11th of August 2014, the new GNS3 will be more polished and will migrate to a multi-vendor emulation platform. For those using this tool, it’s a well known fact that GNS3 […]

EGP

Today I came across an old Cisco router with original IOS image. Big surprise (at least for me) when I did check what routing protocols are supported on this router: I was out of the game, or better not even yet had discover the networking games, when the EGP was still out there and available […]

Troubleshooting with Wireshark [Riverbed lab kit]

A while ago I attended a Wireshark webinar from Riverbed in which they presented the tool, some beginner and intermediate users troubleshooting scenarios and some lab kit. Now I got an e-mail that they made it available for download at http://www.riverbed.com/wireshark-virtual-tour Part of this Lab Kit were available in the Virtual World Tour 2014 webinar […]

Live digital threats

I wanted to bring these free tools to my blog to keep track of them, as most probably I will forget about, and to share with anybody interested in gathering information in the security areas. First tool was revealed to my in tweet from Greg Ferro: Blog post: Response: Digital Attack Map http://t.co/rEhfYAN77c pic.twitter.com/0O1L6kELsK — […]

Cisco switches and smartport macros

Smartport macros are not more than some templates you can define on Cisco switches that will apply the same configuration on multiple ports. It’s not a subject that needs too many discussions, but it can be useful for your Cisco certification preparation or real life Cisco switch administration. Configuration is very simple and it goes […]

Cisco STP forward-time command trick

This is more a topic for exams, like Cisco CCIE, but also it can appear in real-world environments. Consider the following simple topology: SW1 is the spanning-tree root bridge for all VLANs. Imagine that you have a request which ask you that when a port becomes active, no matter of VLAN, it should wait 10 […]

EtherChannel over 802.1q Tunneling

Consider the following topology: We have one Customer with two distributed locations (SW1, R1 and SW2, R2) connected over Provider backbone. What we want to create is something like this: If Provider support 802.1q and L2 tunneling we can achieve a nice Etherchannel between our 2 remote locations with direct CDP visibility. Also STP and […]

Ubuntu OVF images for download

Lately I’m playing a lot with virtualization features and for this I needed a rapid way to deploy from scratch new instances. First I had the virtual machines converted to templates, but then I had to rebuild from zero the entire ESXi environment and those images were gone. I realized then it was more easier […]
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