Does anyone have this? i saw the old thread but i can't get the VM to boot in vCenter or Fusion.
Tuesday, August 17, 2021
OSPF Large area vs many areas.
We have WAN network of about 30 branch offices. Currently they have a main L2 link and LTE backup. All branch offices live in single OSPF area which has three ABRs, two for L2 links and one for LTE links. All links are network type point to point. Each branch office has 3-4 local /24 networks which, for historical reasons, cannot be aggregated. (BO addressing is like this: 10.[a-d].x.0/24). The number of branch offices is slowly increasing.
Everything seems to be working OK. Changes in the network are propagated in decent time . But the change is coming, we are going to build a backup data center and get redundant L2 links for most of the branch offices. Diagram here
Now I have a question. Do I keep current design or change to an area per branch office? I have seen this approach on the Internet and I am not sure it this makes sense. What are implications and limitations? My knowledge about OSPF internals is not deep enough and Cisco design guides do not help much.
I hope this time it will not be to trivial question for the mods and I will not have to move to /homenetworking or sth.
Ethernet not getting IP at office after using VPN at home
Hi folks,
Really helping someone can shed some insight on what's going on as I've run out of ideas...
Situation:
Multiple devices failing to get DHCP lease via ethernet from the corporate network, wifi works fine
Learned info thus far:
Devices know their is a connection (laptops show up when I do 'show mac address-table' on the switch) but it's a 169.x.y.z ip address and Windows says 'Unknown network, no internet connection (public network)' for the network icon.
I thought it was a problem with the switch as all the problematic devices are plugged into the same bank on the same switch (41, 43, 45 & 47). All ports are configured the same way, just like any other data port on that switch.
What I was told as I was leaving which changed things a lot was that they were working fine before the users took them home and connected to their home network using ethernet and connected their work VPN. Since then, while in the office, the ethernet hasn't worked (both the onboard ethernet and the ethernet port on the dock).
Things tried:
nuke the tcpip stack
rebuild the port on the switch (Cisco Catalyst 9000 series I think from memory)
disable/enable NIC
remove the NIC and reinstall
firmware/driver updates (Dell Lattitude 5510's if anyone is interested)
set static ip (can't even ping the default gateway)
swapped cabling
different device plugged into the port
I didn't have an opportunity to try them in another switch port as it's full populated and I couldn't exactly kick a working device off and risk breaking it also (as unlikely as that may be).
I'm leaning towards some broken routing or oddball security policy which has been deployed, like mac security on a switch but from Windows. I can't, however, find anything that's actually wrong when I go down this route.
Monday, August 16, 2021
Is there a way to "learn" networking with Juniper like you would be able to with the CCNA?
Title kinda sums it up, but basically I'm looking to learn networking from the ground up, and I work in an environment with mostly Juniper switches/routers. I have some basic understanding of networking, but am looking to understand things on a level closer to a network engineer.
The issue is, the CCNA covers pretty much everything I need to know, but it's Cisco-centric. The Juniper training materials are incredible, but they're clearly targeted towards people who already have a solid grasp of the fundamentals of networking.
Is there some middleground - a book, a course, etc - where they take a CCNA-type approach to networking, but use Juniper instead of Cisco? I really want to get into the guts of how protocols work. I could just go over the free courses on the Juniper training portal but I feel like I'd just be memorizing commands with no real context or deeper understanding.
10Mbit using SFP on Cisco C9300
Hi All,
I am aware that the Cisco C9300-48UXM doesn't support 10Mbit connections. Only 100/1000/2.5GBaseTX. I've read through previous posts here, but they are all archived so I can't resurrect them.
I'm wondering if anyone out there has tested connecting a 10Mbit device to a GLC-TE in one of the SFP ports? The C9300-NM-8X module supports the GLC-TE and the GLC-TE supports 10/100/1000 speeds. So I am wondering if this is a viable solution.
Thanks!
Using softether, bug with windows bridged adaptors and parsec
I have been using softether to make remote access on certain networks possible, due to a less than adequate laptop.
Regardless, i had 2 ethernet ports bridged together via windows to accommodate other devices across a couple rooms to have a stable network connection and i found out that when using softether's virtual bridge on a bridged adaptor, programs like parsec fail.
As well as RDP didn't recognise my PC or it's ip address.
Is there a reasonable way to bridge the bridges that will not mess with the network stability or is it a null effort. thanks.
What could possibly break a specific subnet across every switch simultaneously and leave other subnets on the same hardware unaffected? (post mortem, I don't want it to happen again)
Environment with a collection of UniFi switches. VLANS are not used. System has been stable with this configuration for > 4 years. No configuration changes were made before the system went down. No power or water incidents. The firewall never lost connectivity across a tunnel from another site, but the configuration page could not be accessed from the LAN, even though it could be pinged. Restarting the firewall did not resolve the problem.
Devices on one subnet and only one subnet repeatedly lost connectivity for a lengthy period of time.
Devices on the same physical wiring would not have any connectivity issues at all.
For example:
PC with IP address of 10.1.1.10 is plugged into a VoIP phone that has an IP address of 10.10.1.15. The phone worked, the PC would not.
PC with IP address of 10.1.1.15 plugged into a network jack with a straight run to switch 1 (out of 5), no connectivity. Change the Ip address of the PC to 10.10.1.20 and it works flawlessly.
Rebooting the Windows server where DHCP lives, the subnet came back up immediately on reboot, then 3 minutes later died again.
Rebooting the SonicWall got the subnet working again, then it died after about 3 minutes.
No excessive traffic spikes. Nothing that looked like a packet storm or a routing loop anywhere.
Eventually I rebooted every switch simultaneously using the Uniquiti Gen 2 cloudkey. Even the switch that has nothing on it but the subnet that never went down. After all of the switches finished the restart the problem was gone completely and stayed up.
I've been digging through the device logs and see the switches losing connectibity with the CloudKey, but other than that haven't found anything unusual yet.
It seems to be some combination of something, but how to identify the specific combination that caused the problem? I've seen hardware fail, you identify the failing component, fix/replace it and life goes on, but there isn't any hardware that actually failed that I can identify as the problem. I've seen packet storms, loops and other faults, but those generate traffic spikes that stand out like a sore thumb. So if not the modem, firewall, server, specific switch or specific access point, what else could this be?
Purposfully Offline network, But now I need it online
Wanted to preface this with the fact that I don't have a massive ammount of networking knowledge and just know the basics to get me by in my day job.
I work in a performing arts venue and a few years we installed a simple Ubiquiti network accross our building. This system is entirly independant from the buildings main IT infrastructure and is intended to be that way. Its set up with a few access points in key locations and then a few seperate VLAN's and is used for us to allow peices of equipment to communcate to each other locally (mixing desks, amplifiers, lights etc etc). This network is intentionally "offline" and has no internet connection as the equipment has no need for a connection. However recently i've run into a few issues that it would be nice to fix but my limited knowledge is limiting me from doing so.
Some of the ubiquiti equipment requires updates, which requires an internet connection (as far as I can tell as I can't seem to find a way to do it offline). Now the company is rather small and the IT department (1 person) is often quite overwhelmed with work and it can be incredably laborious to get answers to basic requests, so it would be nice not to involve them. We have a switch on the main IT network close to the USG of the offline network that is connected to a staff VLAN with internet. Is there a simple way I can take this conenction from a LAN port and feed it into the WAN port on the USG to make a connection? if not what alternatives do I have? or what do I need to make it work?
Most likely once the equipment is updated I would then disconnect as its only for this purpose, althought if it did stay online I guess it would allow me to remotely access and manage the network?
TLDR: Can I take a connection from a LAN port of one network to make a coonection to a WAN port of another network?
Network traffic monitoring software
Is there any network traffic monitoring application for pc? Live tracking of the upload and download traffic?
Question on Cisco C9200L stacking option?
Through searching I can't find any definitive answers but I have a C9200L-48P-4X and am looking to add 2 C9200L-48-4Gs to the mix.
Is it possible to create a stack by adding those 2 4Gs to the 4X or is that incompatible?
Subscribe to:
Posts (Atom)