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August 18 Update - Help section has been updated!

Thanks to everyone who contributed! I've summarized the topics into the help section "What topics can I ask about here?".

August 12 Update – Final week! Cast your votes! Make your edits!

Changes to this Q/A seem to be tailing off. I'll add the on/off topics to the Help sections at the end of this week, including a link back to this Q for reference.

August 6 Update – 2nd inning PUSH!

Please vote, and best if you vote up/down on every topic (aka each answer here.)

I've styled some of the answers to make them easier to glance over from a "this is a list of topics" point-of-view.

This is a community wiki question; Please DO edit existing topics (aka answers here) to add example questions, clarification, etc.

July 31 – A call to arms!

Our site's Help section has a What topics can I ask about here? which currently provides only general guidance about what works well on Stack Exchange sites. I want to expand that section of our help to have specific examples of topics.

Please post answers containing topics you feel are, well, on-topic. That is to say one, specific topic in each answer. (...invent them, cull them from the main site, dredge them up from the Area51 proposal; whatever.)

Everyone is encouraged to up/down vote on as many of the answer/stopics as they wish. When we have what seems like some consensus, we'll harvest the top-voted answers/topics into the Help section.

Let's try to keep the list relatively short; We're hunting for the main topics we want to see.

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  • 3
    Hi Craig, I like the idea of this thread, but could we ask for topics instead of individual questions? A list of individual on topic questions could grow infinitely large...
    – Mike Pennington Mod
    Commented Jul 31, 2013 at 13:20
  • Good point. Edited.
    – Craig Constantine Mod
    Commented Jul 31, 2013 at 13:27
  • 1
    That said, please try to provide examples of the sorts of questions you're talking about. Helps avoid the use of terms that mean different things to different people.
    – Shog9
    Commented Jul 31, 2013 at 20:33
  • PS: Additionally - flashrouters.com - Commercial Support - Does this now qualify these Open Source/ Linux based router tech for NE on SE?
    – Alex S
    Commented Jan 8, 2016 at 4:47

15 Answers 15

Reset to default
18

Enterprise/Service Provider Networks –

Questions one would encounter while operating, maintaining, purchasing, or managing an enterprise / service provider network. The question should be about the operation of your own network.

Enterprise, in this case, means a "business organization", which could be large or small.

Examples:
Q: BGP - Better Enterprsie Multihoming
Q: How can I see which switch ports are not in use?

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  • Not sure I was clear in the main Q: I was envisioning many answers, each suggesting a topic; Rather than an answer listing all the topics which are on topic. So I'm reading this answer as three topics. Thoughts?
    – Craig Constantine Mod
    Commented Jul 31, 2013 at 15:26
  • Ahh, I see! I can break these out into separate topics this evening.
    – Brett Lykins
    Commented Jul 31, 2013 at 20:12
  • I edited out the part about "consumer" gear, since that is being put forth in another answer.
    – Brett Lykins
    Commented Aug 4, 2013 at 23:56
  • 1
    I made minor tweaks to both this and the help center to reflect our general rule that you can target a community "This site is for professional dowgwalkers", and you can define what questions are and aren't ok by their connection to it "Questions should be the type encountered by people while walking dogs for money", but can't be banned based on the user. You can't say, "Even if your question would be ok if asked by someone else, we can tell you walk dogs for fun, so it's off-topic."
    – Jaydles Staff
    Commented Aug 21, 2013 at 20:55
  • The changes I made shouldn't in any way change the questions you're actually allowing/excluding, just the way we're describing them.
    – Jaydles Staff
    Commented Aug 21, 2013 at 20:55
18

Network Design –

This category deals with how to design networks with on-topic network infrastructure. Assuming there are multiple network infrastructure technologies or implementation choices which can achieve the same design goals, questions about the nuances or implications of those technologies are on-topic.

For example, a valid Network Design question might ask about the behavior of a technology in various infrastructure failure scenarios, or brittleness of the design in the face of future growth.

Examples:
Q: Ethernet termination density per rack and space planning
Q: Are there any reasons to not use BFD?

1
  • ...just trying to set the tone to encourage others to post. Please feel free to down-vote this topic into oblivion. :)
    – Craig Constantine Mod
    Commented Jul 31, 2013 at 13:39
14

Questions about Unix / Linux Servers which are running Network Protocols or a Firewall –

Questions about firewalling or network protocols such as OSPF running on linux / unix servers... to qualify under this category:

  • The system must not be purpose-built by a vendor specifically for routing / switching / firewall purposes
  • The system must not have commercial support option for the required routing / switching / firewall function

Examples:

Q: IPTables rules to forward traffic to an external IP
Q: OSPF LSA checksum error

I personally think these should go to serverfault, but I hope the community will vote on the matter. If you want things such as an IBM server running Quagga to be on-topic, upvote. If you agree with me, downvote :-)

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  • ...should we just merge this into the "net proto design/theory" topic that @venti added?
    – Craig Constantine Mod
    Commented Aug 6, 2013 at 15:16
  • 1
    Hi Craig, quagga questions do not require network protocol / design overlap. In the case I mentioned, the OP is seeing LSA errors and simply wants to find where the errors are coming from.
    – Mike Pennington Mod
    Commented Aug 7, 2013 at 0:05
  • As network engineering evolves with SDN and virtualization, there's going to be more an more subject matter involving "software" networking. To dismiss it as not "network engineering" would be unfortunate.
    – Santino
    Commented Aug 14, 2013 at 22:56
  • 1
    @Santino, when did I say quagga is not part network engineering? My reasoning for wanting to punt quagga questions is that ServerFault already does a good job with quagga questions, and quagga doesn't have standardized HW / OS like Cisco or Juniper. As such, quagga is significantly harder to support than one of the commercial appliances; it's much closer to a "server with routing" than a "router". Therefore, we should send quagga to SF. Full disclosure: I have been a rabid linux user for 15 years. SDN is a red-herring: quagga isn't unique to SDN.
    – Mike Pennington Mod
    Commented Aug 14, 2013 at 23:29
  • Maybe this is the wrong example for my argument. That said, my point is network engineering is not just about HW kit anymore. Quagga is one example. What about XNC, Contrail, OpenDaylight, Floodlight, OVS, Cumulus Linux, NSX, etc. All software-based implementations of networking, some from traditionally HW kit vendors. Software implementations and even writing code (onePK, OpenFlow, etc.) will become very relevant to what we do, and as such we should try to support that, not punt it to a forum that doesn't have a clue what those things are.
    – Santino
    Commented Aug 15, 2013 at 1:07
  • @santino, SDN might be relevant for some people. Feel free to add another on-topic suggestion to this thread. BTW, I think you're closer to a Quagga / SDN argument if you mention RouteFlow, which has some Quagga heritage. Nevertheless, I will continue to draw a distinction between "routing on a server" and a dedicated "routing appliance". "servers with routing" should go to SF; dedicated "routing appliances" are certainly on-topic IMHO
    – Mike Pennington Mod
    Commented Aug 15, 2013 at 1:19
  • How to setup a firewall isn't "network engineering". While there are some practices to be discouraged (deny icmp all), most firewalls are vendor specific products, or they're a host based system best dealt with within their specific communities. Routing/switching/bridging is an engineering topic, however, there are better places to ask about zebra/quaaga/etc; I wouldn't answer those questions, but I won't stop anyone else.
    – Ricky
    Commented Oct 28, 2013 at 0:16
  • @rickybeam, I disagree. iptables is too common and too complicated. We will get a flood of low-quality "just give me the solution" type of questions, if google says send them here. A review of SO's recently closed iptables questions shows you the kind of insanity we will start receiving. FYI, the list is short because SO automatically deletes many closed questions
    – Mike Pennington Mod
    Commented Oct 28, 2013 at 3:10
  • Mike, I'm saying we should not cater to host firewall questions -- commercial products, maybe, but they should have their own knowledge bases. Software routing systems are rare enough that I'd allow it -- but I'm not going to answer them. (that's a mess of their own choosing.)
    – Ricky
    Commented Oct 28, 2013 at 17:36
  • @RickyBeam, my point in disagreeing is that we should stop people from answering them on NE. The things we allow now are what google will send to us for a very long time in the future.
    – Mike Pennington Mod
    Commented Oct 28, 2013 at 19:43
13

"Prosumer" Networking Gear –

Questions regarding products that aren't exactly "consumer" grade, because they have the option for a token support contract. They are also a little too cheap to be widely used and understood - i.e. "48-port Netgear" switch, such as the "Netgear Prosafe 48-port GS718TS".

Examples:
Q: Problems Connecting Catalyst 2960G to Netgear Prosafe Via Fibre
Q: Building new network and need 200+ wireless devices

I'll agree that I'm not going to be throwing this switch into my DC anytime soon but I don't believe it qualifies as "consumer" gear. Just "gear no one who is serious about net eng uses". So yes, maybe still off-topic because of the fact that the answers will be scarce, but that would need a little more definition, methinks.

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  • 1
    I personally hate pro-sumer network gear, but at this point I think it's better just to keep the rules consistent so I'll vote it up.
    – Mike Pennington Mod
    Commented Aug 7, 2013 at 16:59
  • I fully agree with Mike's statement, however while I find the term pro-sumer apt and mildly entertaining myself, it does carry a negative connotation with it. To leave bias (even justified bias) out, I think we should refraining from using it and use how they are "marketed," namely entry level business or small business class devices.
    – YLearn Mod
    Commented Aug 12, 2013 at 14:36
  • @ylearn, There is no shame in the term prosumer... quoting from wikipedia... By far the most common usage of the term describes the consumers, enthusiasts who buy products (almost always technical) that fall between professional and consumer grade standards in quality, complexity, or functionality. Prosumer also commonly refers to those products. Semiprofessional.
    – Mike Pennington Mod
    Commented Aug 13, 2013 at 2:28
13

Model/Product Line Features/Differences –

Features supported in the different models of a given product line, with different software versions, licenses, etc.

Examples:
Q: What is the difference between all the switching modes on 6500/7600?
Q: What's the difference between CRS-1 and CRS-3

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Lab Scenario:

Questions about a lab scenario involving equipment we normally consider valid

If you're studying for the CCNP (or another networking certification) at home / work and want to ask why a lab scenario you are building is broken, or need help configuring something; these questions should be on-topic. Even though lab questions are on-topic, we need:

  • topology diagrams
  • config snapshots
  • OS versions
  • type of HW you're using
  • details about relevant troubleshooting
  • "what have you already tried".

Examples:
Q: Strange ping over frame-relay network
Q: How to generate traffic for lab scenarios

Caveat:

We are not here to encourage lazy behavior. The effort you put into a question is positively correlated to the quality of answers you get. Please delay the question, until you have made a good-faith effort at solving the problem yourself.

11

Network Protocols' Design/Theory –

Network protocol questions, like 'Why does Cisco's bgp process pack update packets in path attribute groups like this?' or ' Why does OSPF use this next hop address for these external LSAs?'

Application level protocols (example, host / server protocols above the TCP / UDP / ICMP PDUs) are explicitly off topic.

Examples:
Q: Is it possible to remotely influence BGP localpref?
Q: Are there any reasons to not use BFD?

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  • This type of questions seem to be subjective, depending on how you read some concepts. What if some people start asking "what are some presentation layer protocols"?
    – sdaffa23fdsf
    Commented Aug 5, 2013 at 9:00
  • I think we'd have to decide (on? off topic?) on a Q by Q basis. I think there are some design/theory Qs which would be answerable (a key SE requirement for our stack).
    – Craig Constantine Mod
    Commented Aug 6, 2013 at 15:18
  • 3
    @realdreams, a question about the OSI presentation layer does not qualify as a real network protocol...
    – Mike Pennington Mod
    Commented Aug 7, 2013 at 16:57
  • Mar 20 updates are now in help section.
    – Craig Constantine Mod
    Commented Mar 24, 2015 at 1:28
8

Content Delivery Networks –

Examples:
Q: How to switch to a different Google Global Cache?
Q: Is it possible to disaggregate traffic to CDNs to find out what users are doing?

1
  • 2
    IMO that type of question is not necessarily about CDNs, I think it's more like "how do work around some broken implementations (operational issues)". It seems some people just downvote anything they are not familiar with....
    – sdaffa23fdsf
    Commented Aug 5, 2013 at 9:04
8

Production Troubleshooting Scenarios:

  • Troubleshooting questions can be challenging to handle well on Stack Exchange, because they are so situational. However, they are welcome
  • Please back up answers with facts from the question
  • Please do not answer with speculation about the problem. If something is unclear, ask in a comment.
  • Good / Bad subjective - The community should clarify / close unclear questions

Examples:
Q: Cisco Catalyst cluster heartbeat switch issue - increasing input errors
Q: Finding transparent firewall packet loss

0

Firewall filtering

Firewalls are increasingly a discrete managed product/service. Particularly, they perform deep inspection of packets and go beyond OSI Layer 4 (which is explicitly downvoted at the moment).

For this topic only it's ok to include the discussion of higher OSI layer protocols.

Examples

FTP communication

What do I need to do in order to enable remote HTTPS management of a SonicWall NSA3500

How can I monitor SSH or HTTPS activity on Juniper SRX 240 firewall?

Filtering http/https traffic destined for a juniper router

-6

Consumer/Home Networking –

Questions about anything behind a cable modem at a home. A "home" is when the broadband provider classifies it as "residential."

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  • 3
    I'm hoping this gets down-voted to match the "consumer networking products" topic. :)
    – Craig Constantine Mod
    Commented Aug 6, 2013 at 15:22
  • 6
    I do not agree with this category. Someone who has an interest in networking and doesn't understand something (not brand-related) about the principles of networking, shouldn't be ignored just because he's not a professional. I hope this will be revised. Where a question comes from, doesn't impact the quality of a question in my opinion.
    – Bulki
    Commented Mar 11, 2014 at 6:58
  • Many people built their personal labs behind there residential router, does this mean all their labs are off topic as well?
    – Acyclic Tau
    Commented May 17, 2016 at 19:58
  • note, this is a three-year-old Q-and-A. But it would be off topic if they asked about their home router/internet, and probably on topic if they just asked about the lab they've built. "professional networking in a business environment" is a good litmus test.
    – Craig Constantine Mod
    Commented May 17, 2016 at 20:36
-8

Consumer Networking Products –

Questions about configuring or using consumer networking products (i.e. a Firewall / Router / Switch / Wireless AP that does not have an option for a paid support contract).

I personally don't think these questions belong on Network Engineering; however, we should let the community decide the fate of these questions. If you want consumer networking products to be on-topic, upvote; if not, downvote. I would downvote myself, but I can't :)

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  • 1
    I agree with the principle of this item, but it has some serious collateral damage in ruling out components such as OpenWRT/CeroWrt and Linux appliances that may be thoroughly useful in some legitimate "network-engineering" situations.
    – chrylis -cautiouslyoptimistic-
    Commented Aug 25, 2013 at 0:21
  • @chrylis, please be specific about the consequences of not supporting consumer products. Stack Exchange has supported linux-based networking solutions for years on Super User and Server Fault.
    – Mike Pennington Mod
    Commented Aug 25, 2013 at 0:37
  • I have a particular solution I developed for a client that exemplifies the difficulty I see. What's the best way to get a long explanation attached? Can we open a chat on a wiki answer?
    – chrylis -cautiouslyoptimistic-
    Commented Aug 25, 2013 at 0:39
  • @chrylis, I created a chat room for OpenWRT meta discussion here
    – Mike Pennington Mod
    Commented Aug 25, 2013 at 0:49
-8

Using Enterprise/Service Provider Networks –

Questions from users of enterprise / service provider networks.

I personally don't think these questions belong on Network Engineering; however, we should let the community decide the fate of these questions. If you want users of enterprise / service provider networking services to be on-topic, upvote; if not, downvote.

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  • 2
    I agree (down-voting as off-topic). My reasoning is: If one can contact support for the network, then contact support.
    – Craig Constantine Mod
    Commented Aug 6, 2013 at 15:23
  • 2
    Actually my reasoning is more along the lines of "There is no point in assisting an end-user since there isn't anything they can do (if the problem is the company / ISP's). If the problem is the user's, they should ask on Super User or Server Fault"
    – Mike Pennington Mod
    Commented Aug 6, 2013 at 15:30
-10

Multiple choice questions

Any multiple choice question, such as those found in homework or in certification brain-dump sites... etc...

I personally don't think these questions belong on Network Engineering; however, we should let the community decide the fate of these questions. If you want this to be on-topic, upvote; if not, downvote. I would downvote myself, but I can't :)

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