r/networking • • 2d ago

Blogpost Friday Blog/Project Post Friday!

7 Upvotes

It's Read-only Friday! It is time to put your feet up, pour a nice dram and look through some of our member's new and shiny blog posts and projects.

Feel free to submit your blog post or personal project and as well a nice description to this thread.

Note: This post is created at 00:00 UTC. It may not be Friday where you are in the world, no need to comment on it.


r/networking • • 4d ago

Rant Wednesday!

22 Upvotes

It's Wednesday! Time to get that crap that's been bugging you off your chest! In the interests of spicing things up a bit around here, we're going to try out a Rant Wednesday thread for you all to vent your frustrations. Feel free to vent about vendors, co-workers, price of scotch or anything else network related.

There is no guiding question to help stir up some rage-feels, feel free to fire at will, ranting about anything and everything that's been pissing you off or getting on your nerves!

Note: This post is created at 00:00 UTC. It may not be Wednesday where you are in the world, no need to comment on it.


r/networking • • 5h ago

Other Multi-Vendor Network Management, what do you use?

9 Upvotes

Hello All,

This post is mostly to get an idea of what everyone is using to manage your networking device. There was a few posts I've seen in the past about what others use to manage switching in a multi-vendor network but they were dated and I wanted to see if anything in the landscape has changed for you?

Currently I am in an environment with Aruba-OS (Procurves), Aruba CX's, and the occasional Cisco or Forti-switch. We hope to eventually move everything to CX's but that will take its sweet time. Anyways, onto the main point of this post: what do you use to manage an environment with such a mix?

Personally we use Unimus but it has its limitations (Being slow, buggy at times, and close to a one trick pony.) There are the usual suspects like Auvik (if I get one more advertisement for this I will lose it), or Ansible. I use NetConsole on my lab environment and absolutely love it but they don't have the paid version available ATM.

So please let me know what you recommend/use in your environment that helps ease the burden of switch management!


r/networking • • 4h ago

Troubleshooting Feeling pretty burned right now—our "physically diverse" backup DIA circuit just went down with the primary during carrier maintenance

7 Upvotes

I'm typing this half-awake after a 6am Sunday maintenace window so bear with me if my brain is mush. Before anyone asks, yes, "diverse pathing" was supposedly verified on the SOW when our previous admin signed the contract two years ago. We pay around $1,300 a month for a secondary 1G fiber circuit from a totally different ISP so our 250-person office stays online if something gets cut.

Primary carrier sent an emergency maintenance notice for this morning, which honestly felt like a great excuse to test our SD-WAN failover under zero pressure. Six minutes into their window, BOTH circuits drop simultaneously. I spent twenty minutes checking our HA firewalls thinking I broke a BGP peer or something... nope. Turns out the secondary ISP is just reselling Type 2 local loop off the exact same ILEC fiber vault out by the main road.

Feeling kind of foolish that I trusted a two-year-old doc instead of demanding actual KMZ maps earlier, though I couldnt even get the backup carrier's NOC to confirm the underlying LEC on the phone. how do you all actually enforce true physical diversity on mid-sized sites without getting stonewalled? At this point I'm half tempted to tell management to ditch the second fiber and just throw a 5G enterprise gateway on the roof.


r/networking • • 6h ago

Troubleshooting Need help with a routing issue

9 Upvotes

I can't seem to have my vlans route between eachother from my L3 switch to my router.

For preface, I have ip routing enabled already as well as a DHCP pool that hands out IPs accordingly.

my trunk port on the switch has access to the vlan that im using for my wired data.

Wired data is 86. Ip is 192.168.50.200

DHCP is configured with the default-router of .200

Interface is a trunk port for 2 other vlans.

Router has its LAN 1 port set up as a trunk port allowing the 3 vlans. I also added vlans in the routers database.

I add a static route in the switch to allow 60.0 to the forwarding routers ip of 50.200, and in the router I add a route of 50.0 with a gateway of 60.1

I can't ping them and im not quite sure what im missing.

I do have a gateway of last resort on the switch for 0.0.0.0 0.0.0.0 192.168.50.0 setup too.

Am I missing something? Or just have a misconfiguration?


r/networking • • 12h ago

Design Best resources to prepare for Network Design interviews (L2/L3/L4, Scalability, Reliability, Security)?

27 Upvotes

Hello everyone,

I’m currently preparing for Network Design interviews for Network Engineering roles.

I have a solid understanding of networking fundamentals (L2, L3, L4 protocols, routing, switching, BGP, OSPF, TCP/IP, etc.), but I’m looking to improve my ability to tackle complex network design problems.

Specifically, I’m looking for resources (books, videos, guides, or case studies) that walk through:
Real-world network design scenarios covering L2/L3/L4 architecture.

Scalability, reliability, redundancy, high availability, and security considerations.

Design trade-offs and why one architecture is preferred over another.

Common design patterns that can be reused across different network design interview questions.
End-to-end design walkthroughs that demonstrate how to approach a problem from requirements gathering to final architecture.

Ideally, I’d like to study a handful of comprehensive design use cases that cover enough breadth to help me approach unfamiliar network design questions systematically.
Most resources I’ve found focus heavily on individual protocols or traditional system design rather than practical network architecture design.

Has anyone come across good resources or prepared for similar interviews? Would really appreciate any recommendations or experiences!


r/networking • • 1h ago

Wireless HPE6-A90 – ¿Experiencias recientes con el examen y consejos para la preparación?

0 Upvotes

Hola a todos,

Busco opiniones de quienes hayan realizado recientemente el examen HPE6-A90 (HPE Networking Central).

Trabajo habitualmente con entornos Aruba Central y AOS-CX, incluyendo configuración de switches, despliegues inalámbricos, VLAN, resolución de problemas y gestión de redes.

Hace poco intenté el examen HPE6-A90 y me pareció bastante diferente del material de preparación que había estado utilizando.

Muchas preguntas se basaban en escenarios, a menudo presentados como breves tickets de soporte que requerían interpretar una configuración, comprender por qué algo estaba configurado de una manera determinada o identificar el enfoque más adecuado.

También había preguntas relacionadas con la arquitectura AOS-10, la orquestación de túneles (OTO) y otras funcionalidades específicas de Central. Me estoy preparando para volver a presentar el examen y me gustaría saber la experiencia de quienes lo hayan realizado recientemente.

  • ¿Encontraste un formato similar basado en escenarios?

  • ¿Qué recursos de capacitación o laboratorios oficiales de HPE te resultaron más útiles?

  • ¿Has notado algún cambio significativo en el enfoque o la dificultad del examen últimamente?

No busco preguntas del examen, solo comentarios sobre el enfoque actual y recomendaciones para prepararme de manera más efectiva.

¡Gracias de antemano!


r/networking • • 1d ago

Other DIY fiber splicing

33 Upvotes

We just had an accidental fiber break in one of our locations. Thankfully there was a tech on site that knew how to splice and had his equipment with him.

Now I’m wondering if yall do your own splicing. Is it worthwhile to invest in the tools and equipment for it? I know these types of incidents rarely happen. But thinking back on the incident we have; if that happened without the tech there we would’ve been offline at least for hours.


r/networking • • 1d ago

Design CloudFlare One - Reliability and Alternatives?

9 Upvotes

Hiya,

I've got an EOY task to get all corporate traffic on- and off-site behind a WSG or similar. CloudFlare One is free up to 50 seats so great for testing out right now. I was wondering if anyone had experience using it as a posture-only tool on-site and SWG + always-on VPN tunnel off-site, issues with reliability, or any other big downsides. Also wondering if anyone has alternatives that aren't too bad in price and are similarly easy to implement and have VPN+SWG functionality. Currently running low-end Sophos firewalls and they are not candidates for replacement at this time as much as I'd love to move to Fortigates. TIA!


r/networking • • 2d ago

Troubleshooting Intermittent packet loss on one access switch port that disappears when I change the cable

11 Upvotes

I'm dealing with an annoying problem at a small office with about 40 users. One workstation has been reporting random slowdowns and dropped Teams calls for about two weeks. On the switch, I can see occasional input errors and CRC counters incrementing on that port, but they aren't huge numbers, and the link stays up at gigabit speed.

I replaced the patch cable and the issue vanished for two days, then came back. I tried another port on the same switch, and it behaved fine for a day, but now the new port shows a few errors too. Wall jack testing with a basic tester shows everything wired correctly, though I know that doesn't prove quality.

I suspect the cable run inside the wall, maybe near a power line or with a damaged section, but I'd like to verify before pulling a new one. What steps do you take in a case like this? Do you recommend a proper cable certifier, or are there other quick checks that give useful information? I'm also wondering whether duplex or auto-negotiation issues could be involved, since the NIC is older. Any advice would be appreciated, because i'd like to fix it permanently and not keep swapping patch cords.


r/networking • • 1d ago

Switching Command to view the power of a fiber in Alcatel switches

1 Upvotes

I'm just starting to use Alcatel switches, and I need to know the command to check the fiber power.

I'd like to know if anyone could help me with this question.

The models I'm using are:

6850

6860

6450


r/networking • • 2d ago

Routing How do you handle conflicting/stale AS-SET data when auto-generating BGP filters?

15 Upvotes

I work at Inter.link, and most of our peering config is automated now (PeeringDB + IRR -> prefix-lists -> push). The part that still takes manual time isn't the tooling. It's the data going into it.

The pipeline is pretty standard:

Pull the peer's AS-SET and max-prefix values from PeeringDB
Expand the AS-SET against IRR (bgpq4)
Validate and normalise internally
Generate prefix-lists and push

That works until it doesn't. The problem that keeps biting us is AS-SET name collisions. The same name can exist in RADB, ALTDB, RIPE and others, each with different members. Some copies are stale and some are a completely different org's object. Pinning sources with bgpq4 -S helps, but then you need to know which source is right for each peer. The irr_as_set field in PeeringDB often isn't in SOURCE::AS-SET format, so you end up guessing.

The options I can see:

A fixed source priority (RIR databases first, RADB/ALTDB last)
An internal override list per peer
Diffing the expansion against what's actually announced, or against RPKI ROAs, and flagging big deltas
A human looks at it

None of these feel great on their own.

The same problem shows up elsewhere too: max-prefix values in PeeringDB that haven't been touched in years, and RTBH/blackhole communities that are only documented on a webpage or in a PDF (or nowhere) instead of anywhere machine-readable.

Automation actually makes this worse. A bad record used to get caught by whoever was typing the config. Now it lands on every edge router in minutes.

Curious how others deal with it:

Do you mirror IRR/PeeringDB locally or query the public sources directly?
How do you resolve conflicting or stale AS-SETs: source priority, overrides, something smarter?
Do you run automated sanity checks before external data becomes config (prefix count deltas, RPKI cross-checks, etc.)?
Where does the industry most need better data standards? Publishing blackhole communities in a machine-readable way seems like an obvious one to me.

I'm especially interested in hearing from people running multi-AS or multi-region networks.


r/networking • • 2d ago

Troubleshooting Need help accessing Dell PowerConnect 5524 console – unusual baud rate/output

0 Upvotes

Hi everyone,

I recently bought a secondhand Dell PowerConnect 5524, but I'm having trouble accessing it through the console port.

I've tried different baud rates, from 2400 up to 115200, using a USB-to-serial adapter. I've also tested different configurations for data bits, parity, stop bits, and flow control.

I've attached the two images showing the only configurations where I actually get console output.

Some observations:

  • At 2400 baud, I get output, but it's essentially the same garbled/unreadable output as 9600 baud.

  • The best output I've managed to get so far is at 7O1 although it's still not completely readable.

  • I've tried the standard 9600 8N1 configuration with hardware and software flow control disabled.

  • My USB-to-serial adapter and console cable work perfectly fine with my Cisco and Juniper switches.

I'm wondering if the previous owner changed the console settings or if there's something else I'm missing.

Is there a way to recover or reset the console baud rate on the PowerConnect 5524 without being able to access the CLI?

IMAGES

Any suggestions would be greatly appreciated. Thanks!


r/networking • • 3d ago

Career Advice CCNA done, four years in help desk, and I can't get a network engineer interview. What am I missing?

42 Upvotes

I'm 27 and I've been working in help desk at a mid-size company for about four years, with the last year and a half in a tier 2 role where I handle some basic switch and VLAN work. I passed my CCNA last spring and I've been studying for the CCNP ENCOR since. I also built a small home lab with a few used Cisco switches and a virtual router setup, so I can practice routing protocols and ACLs.

Despite all that, I'm not getting traction on network engineer applications. I've sent about 60, and I've had maybe four recruiter calls that went nowhere. The feedback, when I get it, is usually "we're looking for someone with more hands-on production experience."

My current job doesn't give me many opportunities to work on real network changes, and the senior engineer is reluctant to delegate. I'm worried I'm stuck in a loop: I need experience to get the job, but I need the job to get experience. Is there a realistic way to break out? Should I look at NOC roles first, or smaller MSPs? And how do you show hands-on skills on a resume when your day job isn't quite it? Honestly any advice from people who made the jump would be appreciated, as i feel like I've done everything except get the actual opportunity.


r/networking • • 3d ago

Design Inherited a poorly documented network infrastructure. Where should I begin?

38 Upvotes

As a junior network admin who inherited the work of too many cooks in the kitchen, I've been tasked with cleaning up a hodgepodge of a network consisting of two dozen network closets, no clear labeling of network drops, and a variety of network equipment that needs to work together.

Here's a breakdown of the environment:

Domain Controllers: We have two DCs (one primary and one failover), both of which function as AD, DNS, and DHCP servers. Some DHCP scopes are configured on them, while others are not. There's also another DHCP server running on the UniFi firewall, which has its own VLANs and is primarily used for security cameras. However, due to some misconfiguration, trusted devices have ended up using those IP ranges as well.

Gateway Layer: At the gateway sits a SonicWall with its own interfaces and subnets that don't exactly match either the DC DHCP scopes or the UniFi VLANs. It also has a host of zones and custom firewall rules with generic names like "My Rule 256" and "My PC to LAN Connection Allowed."

Core Layer: At the core is a Netgear switch with 24 fiber ports. It feeds all the data closets (none of the fiber connections are labeled with source or destination information) as well as the UniFi ecosystem.

Because so many different people have worked on this environment without documenting anything, I have very little idea how things are currently configured. I've been chipping away at this for a couple of months, but I'm not making much progress.

Where should I begin? What should I prioritize?

Ultimately, this is what I'd like to accomplish:

  • SonicWall: Eventually becomes the default gateway and DHCP server for the entire network.

  • Core: Eventually gets upgraded to a UniFi switch with fiber connections to route traffic throughout the network.

  • Domain Controllers: Continue providing AD and DNS services for the network.

Am I overlooking anything? Is there a recommended order of operations for tackling a project like this?

I'd especially appreciate advice from anyone who has inherited a similarly undocumented network. What would you tackle first, and what tools or documentation methods would you recommend?


r/networking • • 3d ago

Troubleshooting unclear interview question

45 Upvotes

Hi guys,
a friend of mine was asked a question during an interview, and the interviewer's answer, to my knowledge was wrong, but I wanna know if there is any possibility that it could be the answer

the question was
the network is PC1 <-> Switch <-> Router <-> Router <-> Switch <-> PC2

ping between the PCs is working, all other traffic is not
My friend immediately said that it is probably an ACL or endpoint firewall issue, but it was not the case, all traffic is permitted

i told my friend that i think it might be due to routing issue, like PBR, which could affect this, like ping is going through the correct route, but PBR is causing a loop or null

but the interviewer said it was TTL, without further explanation

is there anyway that TTL could be the issue? Even though ping is working?


r/networking • • 3d ago

Other download caching setups

17 Upvotes

We are a university and are starting to feel the hit from GTA6 preloading. I'll generalize and say we have about 25,000 users sharing 100G to various ISPs. We have a small cache for Apple things, though we're slowly getting closer to the minimum requirement for an Apple Edge Cache.

I've been toying with some old Cisco C220 M5 servers trying to setup LanCache to see if it can help, but I am wondering if I'm wasting my time with once in a decade event.

Anyone successfully using LanCache or something else to help with bandwidth relief? Or maybe failed miserably and would share your story?


r/networking • • 3d ago

Design Cisco Nexus VPC vs ESI Multihoming which to chose as firewall aggregation and why?

14 Upvotes

We are currently in the process of redesignen our network. We want to place a Pair of Cisco Nexus:

n9k-c93180yc-fx3

In between our external and internal firewalls and to do the handoff to our datacenter fabric (arista or cisco nexus) aswell as campus fabric (cisco catalyst).

The firewalls currently are configured in a glorified router on a stick with several virtual firewalls which do OSPF in a seperate vlan. While the client/server/dmz vlans distribute from there.

So initially the switches need to serve l2 redundancy via Portchannels to the firewalls, aswell as to the fabrics (which initially will also just transport l2 segments).

However Ideas have been floating around thinking about the future uses doing vrf-lite to the fabric and diving more into routing on an l3 per port basis. Another one was to use this aggreation pair as the border leaf for both fabrics and skip the additional border leaf pairs.

So the question arose, what l2 redundancy mechanism should we go down? Is it smart to configure vpc in 2026? Or should We just skip straight to ESI Multihoming between the 2?

Both seem to be fairly established in nxos 10.6.4m, but I would like to get some insight into other ppls experience with either functionality. Thanks in advance!


r/networking • • 3d ago

Troubleshooting Dell Enterprise SONIC

4 Upvotes

Looking for some guidance on the below setup

2x Dell 5224F running Dells version of SONIC with MCLAG and static anycast gateway.

We are seeing an issue where intermittently clients are failing to renew their IP address and a force renew or reboot is required to obtain an IP.

We are using a IP helper to relay the DHCP request to the Windows DHCP server in a different network.

From some research it seems like the DHCP reply is not returning on the MCLAG member that originally received the DHcP request.

Documentation talks about using link select options to adjust the Giaddr to a unique address on the switch the request was received on to ensure the reply returns to the correct switch back to the client but, have not been able to get this working and suspect it’s related to configuring Windows server to support DHCP option 82 / 5.

Suspect this would be similar in any MCLAG configuration.


r/networking • • 2d ago

Troubleshooting Docking Station's Ethernet Issues

0 Upvotes

Has anyone experienced issues with docking stations not passing Ethernet connectivity to laptops? Our Helpdesk recently purchased several ICY BOX IB-DK2102-C docking stations, and so far, they've been nothing but trouble. Almost every time a user receives one, we encounter connectivity issues.

Interestingly, the ip phones work fine, but the laptops connected through the docking stations have no Ethernet connectivity.

Has anyone experienced similar issues with this particular model? If so, have you found a reliable solution or workaround?


r/networking • • 3d ago

Switching Alcatel Lucent OS6450 Console Access

3 Upvotes

It's my first time to configure a switch and i have this Alcatel Lucent OS6450 P24X and I'm trying to access the console on putty.

I tried this setup i found on youtube. From the Switch console>Straight-through rj45 cable>db9-to-rj45 adapter>rs232 to usb>laptop. I verified the com port on device management but the screen on putty is blank.

Also tried using a different baud rate but it still doesn't work.

What did i do wrong?


r/networking • • 3d ago

Switching Phased migration from flat network to segmented network

19 Upvotes

Hi all,

My team is planning on taking our current network, which for the most part is everything in the default vlan, and using the same firewall interface, and some limited secondary IP addresses, as its gateway. We have no sub interfaces to inter vlan routing.

We recently had a network review done by an engineer, he recommended we move to design segmentation and migrate towards it.

He recommends that we keep our current setup in place, then open up a new port on our core switch to the firewall, and setup VLANs with respective networks on the VLANs doing 802.1q, all on one interface.

Ideally we would create a few basic VLANs and move in and test low risk devices and users, then move from there. We would want to do all this in controlled phases and out of production. All the while everyone and everything that is not apart of our test VLANs will run through the old firewall interface with it’s old ip address / default vlan.

My question is, is there anything I need to take into consideration when running two links to the firewall like this at once? Ideally we would like to maintain 100% uptime for devices that are not being tested in our VLANs.

Has anyone ever done something like this?

Thanks


r/networking • • 4d ago

Monitoring Are you auto-opening tickets with your monitoring systems?

19 Upvotes

Our monitoring system has the capability to integrate with our ticketing system, but I’m hesitant to do so. Currently the network team gets email and teams alerts from our monitoring system when a device or interface alerts.

Typically an actual ticket won’t get opened unless a user calls in to report or problem, or if one of us decides the event is severe enough that we should document it with a ticket.

If we start auto opening tickets directly from alerts I guess my biggest concern is politics; “you guys didn’t respond to a ticket in 8 hours” kinda thing.

We’re a small team and don’t have a 24/7 NOC. We also have a lot of rural sites so things like power issues, wan issues, etc tend to happen a lot, especially during nights and weekends. And usually no action can even be taken on a down site until the next morning and on a business day at that.

I’m just curious what other smaller shops are doing. Obviously a global corp with follow the sun coverage is going to operate differently.


r/networking • • 4d ago

Career Advice Lancom

8 Upvotes

Hi

I’m currently applying for a job as consultant for a SME MSP. They use lancom for wifi, network switches and watchguard for firewall. Lancom is totally unknown for me. Is it a good brand? Also watchguard is known for me but not sure if it’s a good brand. Was wondering some feedback from other professionals. I currently have 7 YOE but somehow it feels like a step back as they seem to be more b brands?