This is not my question but I came across it in my searching. It has many views (25K+), it appears to be a valid question, it has lots of answers attempting to genuinely solve the problem; but it was closed due to "Requests for product, service, or learning material recommendations are off-topic". It not did seem to fit THAT bill at first glance, but I am definitely not one adept at deciphering such things.

In the end, it seems like a valid, relevant, and answerable question with a lot of interest and seems like something that would not normally be "closed". I am hoping someone can review and reopen if it meets the criteria to do so.

Question is here: How to configure iptables to use apt-get in a server?

  • 1
    It is closed because it is not a good example of an SF question.
    – user9517
    Commented Dec 17, 2017 at 18:44
  • 4
    I'd certainly like to hear from some of the people who voted to close it. The listed close reason makes no sense at all, and I don't see why this should be closed at all. It's a clear question with a definite solution. Commented Dec 17, 2017 at 18:55

5 Answers 5


I agree that the close reason appears inappropriate. The fact that there's so many answers (none of which are complete) suggests the question isn't particularly clear, though. Also, as far as I can tell, the question is incomplete or misleading (setting the INPUT policy to ACCEPT shouldn't fix that ruleset).

Personally, I'd like to burninate the question just so such an appallingly bad ruleset script (aside from the general principle that Friends Don't Let Friends Setup iptables By Hand) doesn't lead anyone else astray, but under the site rules, I think it deserves to stay open because someone could reproduce the problem (probably with an OS newer than Debian Lenny) and provide a complete answer. Before I'd reopen it, though, I'd also like to hear from some of the people who closed it, to get their reasoning. Five experienced regulars have apparently seen something that Michael and I have missed.

  • I definitely would like to see a better question with a better set of answers, but that's not how things go sometimes. In terms of it being closed, I figured I was just missing something and if not, it would nice to see it reopened.
    – Damon
    Commented Dec 18, 2017 at 3:17

I was one of those who VTCed, and though I can't remember my choice of reason it's clear it wasn't "product recommendation". Here's what I think now.

  • Firstly, it's a "please fix my iptables" question that doesn't post the complete, live ruleset (iptables -L -n -v); those are damned from minute one, in my eyes. While a quick update can rescue such a question, after seven years it seemed unlikely in this case.

  • I dislike such questions anyway, as the solution details are often highly specific to the ruleset in question (I miss the old "too narrow" close reason); to make them scale to others, an answer has to be written that becomes a general primer on iptables, and that is too broad / a request for learning materials.

  • The question, being unanswerable in its present form (no live ruleset) was still attracting noob-quality "here's what worked for me" answers seven years after it was asked. The author clearly has no intention of cleaning up behind him/herself, so closing it was pretty much a mercy killing in that it stopped any more ill-thought-out answers from being posted.

Without endorsing Womble's attitude to hand-written iptables rulesets (I do those all the time, but then I actually did write the book on it :) I would also like to see the question burninated. But closing it is nearly as good.


What you can see from the question is who voted for closing the question. What you cannot see is which close reason each voter chose. The exception to that rule is that if a question is closed as off-topic any of the standard reasons given by two or more voters will be presented with their names under it.

On that particular question you can see that three people voted for the standard close reason with the wording:

Requests for product, service, or learning material recommendations are off-topic because they attract low quality, opinionated and spam answers, and the answers become obsolete quickly. Instead, describe the business problem you are working on, the research you have done, and the steps taken so far to solve it.

I wasn't one of those three people, but my guess is that they saw the question as a request for learning material recommendations.

I don't think it is the best suited close reason for that question and as you can see I picked a different close reason. Which particular close reason I picked at the time I cannot remember.

What I see as problems with that question is that firstly those iptables rules aren't implemented in the best way, but more importantly that it doesn't show any attempt at narrowing down the problem to any specific rules in the ruleset.

That the question doesn't attempt to narrow the problem down to a specific rule and that it doesn't contain any information about what packets are actually being observed on the network is the reason I am not going to vote for reopening the question.

  • Thank you for the insight. Not to be argumentative but IMO, they really needed to post their entire iptable for troubleshooting, as convoluted as it might be and as poorly as their iptable might be implemented. And they did try to narrow down the problem to a specific rule via the OPs "...After some attempts, I find that the problem is in the INPUT policy, and not..." Personally as a person seeking help from peers, I would hope some unintentional ignorance would be acceptable.
    – Damon
    Commented Dec 18, 2017 at 18:45
  • 2
    No. If you're seeking help from peers in this case, you're a professional sysadmin who understands IP networking and the nature of first-dispositive-match-wins filters; unintentional ignorance at that level is sloppiness. Or you're not, in which case you're not asking peers, you're asking seasoned pros to give up their time to help you.
    – MadHatter
    Commented Dec 21, 2017 at 12:07

Here's another of the close voters. I agree that the reason given seems weird - though it's unfortunately easy to click on the wrong the close vote reason and then you can't easily go back and fix it.

However, looking at the question, it's the end of it that jumps out at me:

then when I run apt-get I obtain:

core:~# apt-get update 0% [Connecting to ftp.us.debian.org] [Connecting to security.debian.org] > [Conne

and it stalls. What rules I need to configure to make it works.

The specific things that make me want to burninate this question is:

  • Lack of firewall logs. The first thing to do, which every sysadmin should know, is look at the logs. You don't do trial-and-error, you do trial-and-verify.

  • The words "What rules I need to configure to make it works." If the question had been "How do I figure out what rules I need to make it works" I would probably have left a comment containing the previous point, and it would've been solved.

However, I think if I saw it today, I might punt it over to Unix/Linux instead; they're much more welcoming to newbies - and rightly so; that site isn't restricted to professionals.

  • I think you got it; it really should be posted on Unix SE or Superuser. Thank you for the insight!
    – Damon
    Commented Dec 21, 2017 at 15:00

I think instead of re-opening that, I think it might be better to ask a more generic question asking 'what ports and protocols apt could potentially use during the updating process' with a sub-question of what the minimal rule set would you use to 'permit these protocols/ports from the local system using iptables'.

After the better question/answer has been generated we could mark the older question as a duplicate so that it links to the better version of the question.

  • +1 and probably on the non-professional SE sites.
    – Damon
    Commented Dec 21, 2017 at 14:59
  • I'd prefer a question that goes even further into generic: "How do I troubleshoot firewall rules".
    – Jenny D
    Commented Dec 21, 2017 at 18:29

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