Some interesting stuff I found on IX LANs

Re:Some interesting stuff I found on IX LANs by protocolture on Thursday September 25, 2025 @06:54AM (#45371410)

One of my past employers had a crazy simple networking philosophy. It killed me. He once had his provider shut the port facing his core switch down, due to STP BPDUs being transmitted. To remedy this, instead of disabling the feature on the switch, he replaced it with an unmanaged switch that doesnt speak STP.

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Re:Some interesting stuff I found on IX LANs by ThePowerOfFuet on Thursday September 25, 2025 @07:20AM (#45371552)

He had no business managing a network.

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Re:Some interesting stuff I found on IX LANs by protocolture on Thursday September 25, 2025 @07:25AM (#45371574)

He had a particular niche that had few requirements on complex networking, and a business plan that was so brain dead simple it could be achieved easily.

But yeah, really nice guy but unable to expand beyond that paradigm.

I once helped him deal with a fibre ring, where there were 5 sites in the ring, but only 2 internet services. So sites 3, 4 and 5 had to communicate via sites 1 and 2.

His team had put a sophos firewall, with NAT, and no routing, on every fibre connection and called me when it didnt work.

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Re:Some interesting stuff I found on IX LANs by api on Thursday September 25, 2025 @10:33AM (#45373075)

That's not great, but it's better than the opposite. I've been in networking for ages and have observed that most networking people will, as a rule, make networks as complicated as possible.

Why have one layer of NAT when you can have four or five? Why not invent a bespoke addressing scheme? Why not cargo cult the documentation and/or scripts and config files from Stack Overflow or ChatGPT?

Under-engineering is an easier problem to solve than over-engineering.

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Re:Some interesting stuff I found on IX LANs by bombcar on Thursday September 25, 2025 @02:47PM (#45377124)

Seriously, the number of setups where "they gave us 255 VLANs, use them all!" I've seen is amazing.

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Re:Some interesting stuff I found on IX LANs by mleonhard on Thursday September 25, 2025 @05:13PM (#45379155)

I took an "Architecting on AWS" class and half of the content was how to replicate complicated physical networking architectures on AWS's software-defined network: layers of VPCs, VPC peering, gateways, NATs, and impossible-to-debug firewall rules. AWS knows their customers tho. Without this, a lot of network engineers would block migrations from on-prem to AWS.

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Re:Some interesting stuff I found on IX LANs by protocolture on Friday September 26, 2025 @12:51AM (#45382785)

Ages ago I deployed a sophos virtual appliance in AWS, so I could centrally enforce some basic firewall rules, in a way that my management could understand. There was only 1 server behind it, the same thing could have been achieved simply using the standard built in security rules. I think about it often.

I do find Azures implementation of this stuff pretty baffling. Just in, networking concepts being digested by software engineers, and then regurgitated into a hierarchy that makes sense to them. Not impermeable, just weird.

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Re:Some interesting stuff I found on IX LANs by p_l on Friday September 26, 2025 @08:56AM (#45385984)

Main source of issues leading to overcomplex networking that I ever seen was "every VPC gets a 10./8" like approach replicated, so suddenly you have complex time trying to interconnect the networks later.

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Re:Some interesting stuff I found on IX LANs by api on Friday September 26, 2025 @11:58AM (#45387978)

IPv6 solves this but people are still afraid of it for stupid reasons.

It's not hard, but it is a little bit different and there is a small learning curve to deploying it in non-trivial environments.

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Re:Some interesting stuff I found on IX LANs by p_l on Friday September 26, 2025 @12:20PM (#45388203)

Another issue (also driving some of the opposition to v6) is the pervasive use of numerical IPs everywhere instead of setting up DNS proper.

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Re:Some interesting stuff I found on IX LANs by api on Friday September 26, 2025 @01:09PM (#45388758)

I think this part is somewhat legitimate. Every network engineer knows "it's always DNS," to the point that there are jokes about it. DNS is a brittle and inflexible protocol that works well when it's working, but unfortunately network engineers are the ones who get called when it's not.

A superior alternative to DNS would help a lot, but getting adoption for something at that level of the stack would be very hard.

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Re:Some interesting stuff I found on IX LANs by p_l on Friday September 26, 2025 @03:12PM (#45389966)

I find that a lot of "it's always DNS" falls down to "I don't know routing beyond default gateway" and "I never learnt how to run DNS". Might be a tad elitist of me, I guess, but solid DHCP, routing, and DNS setup makes for way more reliable network than anything else.

DNS just tends to be part that is visible to random desktop user when things fail

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Re:Some interesting stuff I found on IX LANs by protocolture on Tuesday September 30, 2025 @12:48AM (#45421988)

>Might be a tad elitist of me, I guess, but solid DHCP, routing, and DNS setup makes for way more reliable network than anything else.

Depends on the network. If you are talking about a branch office, for sure.

>I find that a lot of "it's always DNS" falls down to "I don't know routing beyond default gateway"

I see it mostly with assumptions. Like DNS Server B MUST SURELY be configured the same as DNS Server A, thus my change will have no unexpected consequences.

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Re:Some interesting stuff I found on IX LANs by p_l on Tuesday September 30, 2025 @05:53AM (#45423698)

Solid management of the services is important, yes. Also being prepared for when requirements change. I remember to this day when a bunch of small (rack-scale) deployments suddenly needed heavy-grade DNS because one of the deployed projects would generate a ton of DNS traffic. My predecessor set up dnsmasq, I didn't have a reason to change it before that, afterwards we had to setup total of 6 DNS servers per rack (1 primary authoritative, 2 secondary updating themselves from authoritative, 3 recursive).

I would say situation also changes a lot if you know/can deploy anycast routes for core network services - for example fc00::10-12 will always be recursive nameservers, and you configure routing so that it picks up the closest one, etc.

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Re:Some interesting stuff I found on IX LANs by kjs3 on Friday September 26, 2025 @12:18PM (#45388183)

I had a very interesting conversation with an AWS guy about how hard they tried to make sure things like Wireshark worked the same inside AWS, because they had some much pushback from network engineers that expected their jobs to be exactly the same inside as on-prem.

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Re:Some interesting stuff I found on IX LANs by protocolture on Thursday September 25, 2025 @07:14PM (#45380521)

I have one customer, who runs a large wireless network, who when trying to design it has obviously taken lessons from US WISP operators on facebook managing trailer parks, and implemented a really low rent high complexity customer hand off circuit from that paradigm for one of his most valuable business customers. It worked, but was actually way more complex than he needed.

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Re:Some interesting stuff I found on IX LANs by kjs3 on Friday September 26, 2025 @12:03PM (#45388040)

most networking people will, as a rule, make networks as complicated as possible

Yeah, we are kinda like that. So many toys...why can't I use them all.

Seriously, tho...the worst is when you go in and you can tell immediately "oh, the guy running this is trying to get his CCIE cert", because there's all sorts of weirdness you'd never/rarely do in a prod network, but it's on the cert test so lets try it out. YOLO!

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Re:Some interesting stuff I found on IX LANs by kc3 on Thursday September 25, 2025 @06:53PM (#45380319)

It has been a while, but I have seen some switches that don't "speak" STP but still forward the BPDU messages (so other switches receive them and still detect loops through the "non-STP switch") and other switches that drop the BPDUs (so other switches/bridges cannot see them, possibly leading to a Layer 2 forwarding loop through the "non-STP switch").

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Re:Some interesting stuff I found on IX LANs by protocolture on Thursday September 25, 2025 @07:11PM (#45380499)

Yeah I had a TP Link in my homelab that I broke in half that did stuff like this.

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