Posts tagged HowTo
Hello everyone. I know I’ve been neglecting this blog for too long. Can’t promise that things are going to change, but I have a good post for today.
I was recently exposed to some new technology while working with a customer. I had to learn it pretty quickly. This post is about a new feature in the Cisco ASA 8.4 code called Bridge Groups. This is essentially the addition of BVI interfaces, which have existed in IOS forever. This feature is useful when running an ASA transparently, but not physically inline. Running a firewall physically inline works well, but it can limit you to the number of available interfaces you have on each firewall. Adding physical interfaces to a firewall is expensive. This feature also saves you from using a context per firewalled VLAN on your ASA. Here we’ll use a 3750 for physical connectivity and use BVIs to force traffic through the firewall. Here is the physical topology:
I’ve been meaning to post this for some time. Awhile back there was a thread on Networking Forum where someone mentioned that 2960s can route now. The 2960 is now a layer 3 switch. I was skeptical, but then I was pointed to this link. I was very, very surprised. I’m not sure why Cisco decided to add this functionality to the 2960s, but I’m definitely grateful. As of 12.2(55)SE, 2960s are layer 3 switches (with some limitations which I’ll cover later). This knowledge came in handy shortly after reading that thread. I was working on a circuit upgrade for a remote side at my previous company. The circuit was ordered incorrectly and I ended up in need of a layer 3 switch ASAP. The tech we’d sent was leaving the next day, so there was no time to ship him anything. Luckily, we had some 2960s on site.
Today we’ll go over the process to connect an IOS voice gateway/CME (Call Manager Express) to the PSTN. I set this up last night and thought it would be a good post. I’ll briefly touch on using a SIP trunk as backup/failover too.
I’ve been running a SIP trunk to Flowroute for quite awhile, but I just recently got a “landline” from my ISP because they’re doing a promotion where it’s basically free. I’m keeping my SIP trunk, but I’ll be using it as backup since all US calling through the ISP is free. I’m using a 2811 with an NM-HD-2V and a VIC2-4FXO.
First we’ll verify that the card is recognized and working:
EDGE#sEDGE#sh voice port summ IN OUT PORT CH SIG-TYPE ADMIN OPER STATUS STATUS EC =============== == ============ ===== ==== ======== ======== == 1/1/0 -- fxo-ls up dorm idle on-hook y 1/1/1 -- fxo-ls up dorm idle on-hook y 1/1/2 -- fxo-ls up dorm idle on-hook y 1/1/3 -- fxo-ls up dorm idle on-hook y
Everything looks good there, the router is recognizing the card and its ports. 1/1/0 is connected to the ISP’s MTA.
Now we’ll configure the dial peers:
Dropping in to do a quick post today. Sorry for the ridiculous lack of content lately. I’ve been busy with finding/changing jobs and new responsibilites and all that.
Today I’m going to cover “object groups” on ASAs. I was never a big fan of these, which I realized had a lot to do with using them behind others, not actually writing them myself. It takes awhile (for me, at least) to wrap your head around what the person before you was trying to accomplish. This is what put me off object groups. Though, I discovered that if I write them myself, I love them, lol. They can be hugely useful. They’re even available in IOS now (as of 12.4(20)T). Here’s an example of when they’d be used:
It’s Jared from CCNPJourney.com. Colby had asked me a couple weeks ago if I would be interested in posting some articles on his blog as he’s been fairly busy lately, and of course I said yes. So I thought for my introductory post on the blog I would do a brief write-up on how to use Iperf!
For starters here’s a little bit of info on Iperf. Iperf is a tool that many system/network admins use to measure the bandwidth on a network, as well as the quality of the path on that network. It is capable of generating traffic using TCP and UDP. The TCP and UDP tests are useful for performing the following kinds of tests:
- Latency (response time or RTT): can be measured with the Ping utility.
- Jitter: can be measured with an Iperf UDP test.