# Problema de instalação: \`getaddrinfo: Nome ou serviço não conhecido\` **URL:** \ **Category:** Product Support\ **Created:** [Maio 4, 2018, 7:23pm UTC](https://meta.discourse.org/t/install-problem-getaddrinfo-name-or-service-not-known/86783 "2018-05-04T19:23:52Z")\ **Posts on this page:** 1\ **Showing post:** 2
**Author:** ![mpalmer](https://sea3.discourse-cdn.com/meta/user_avatar/meta.discourse.org/mpalmer/32/45740_2.png) [@mpalmer](https://meta.discourse.org/u/mpalmer)\ **Post date:** [Maio 5, 2018, 1:06am UTC](https://meta.discourse.org/t/install-problem-getaddrinfo-name-or-service-not-known/86783/2 "2018-05-05T01:06:27Z")
Check if it’s a recently-introduced Docker bug by downgrading to 18.03. Can’t say it’s likely to fix it, but it’s easy enough to try it first just in case. Modify the app.yml to run the ping test before anything else; that’ll rule in (or out) problems with the app container itself versus network issues. After that, you’re in `tcpdump` territory. Capture DNS packets going over `docker0` with something like `tcpdump -i docker0 -n port 53`, and make sure the packets are at least getting onto the network. Then make sure they’re getting _out_ by capturing on `enp1s0` as well – and make sure they’re gooing out with the machine’s public IP, rather than some internal IP. If the firewall’s too restrictive, the packets won’t show up at all on one of those `tcpdump`s, and if they’re on `enp1s0` but with a private IP, then the NAT config’s busted. If the packets are going out but not coming back, there’s upstream network problems (or an `OUTPUT` rule that’s eating them at the last minute), but given you’ve got some DNS resolution on the machine, the problem’s unlikely to be there. If the DNS response packets are coming back in part of the way, then it’s incoming firewall rules that are the problem, and if they appear to be making it all the way back to `docker0`, dump the `veth` interface for the container to double-check, and if they’re there too, something’s setting up iptables rules inside the container, and you’re back to giving Docker some serious side-eye. --- _[View the full topic](https://meta.discourse.org/t/install-problem-getaddrinfo-name-or-service-not-known/86783)._