epmd does not support binding to an IPv4 address anymore

Status changed to 'Confirmed' because the bug affects multiple users.

Workaround for me: recomplied whole erlang source _without_ CPPFLAGS=-DEPMD6 in debian/rules file. It would be great if epmd could listen ipv4 and ipv6 at same time.

Poking at this a bit it appears that epmd will bind everywhere by default, specific IPv6 addresses but not specific IPv4 addresses; so by enabling IPv6 support, we've broken anyone who's a) disabled IPv6 or b) trying to limit access to a single IPv4 address.

wow

@James Page,

on my specific setup epmd was starting just fine if there is no excplicit IPv6 bind address set (via the ERL_EPMD_ADDRESS env). On `netstat -ntlp` epmd was visible and listening to ::1. IPv6 on box was disabled per https://wiki.ubuntu.com/IPv6#Disabling_IPv6

I'll assume it may be working fine for a) if you don't specify a bind address tough I didn't test this. Unfortunately I've changed my setup and I'm unable to confirm this.

FTR: upstream packages (via Erlang's Ubuntu repository) are compiled with IPv4 and this is probably the easiest workaround for the case.

Since by default IPV6_V6ONLY option is *turned off* by default for ipv6 sockets in Linux it is possible to use the IPV4-mapped IPV6 addresses to do the binding [1].

What I have tried was:
$ export ERL_EPMD_ADDRESS=::ffff:127.0.1.1
$ epmd -d
$ netstat -npta | grep 127.0.1.1:4369
tcp6 0 0 127.0.1.1:4369 :::* LISTEN 3544/epmd

[1] http://en.wikipedia.org/wiki/IPv6#IPv4-mapped_IPv6_addresses

I have found an interesting merge request for erlang [1].

Looks like during the implementation it's author has fixed the assumption that if epmd is built with IPv6 support it losses the possibility to bind with IPv4 address.

I have cherry-picked that change and applied it to Ubuntu's erlang-base. Seems to solve the issue.

Can anyone give it a try? It is available in my ppa [2].

[1] https://github.com/msantos/otp/compare/erlang:maint...epmd-IPv6-node-reg
[2] ppa:dgadomski/erlang

@Dariusz Gadomski,

I've upgraded erlang from your PPA and I can confirm that it epmd (and rabbitmq) is back again starting and responding correctly.

Thanks Marcin.

I got some feedback from the feature author on the erlang-bugs mailing list. He will make a new pull request against the latest erlang. Hopefully it will get merged and we will be able to cherry-pick it and deliver as SRU to Ubuntu.

Has there been any update on this?
(Iknow that's a sad pathetic update.)

David, unfortunately I don't see any updates in this area in upstream erlang.

At this point I can suggest you using either:
1) the version from my ppa [1] or
2) the workaround from comment #6

I will update this bug as soon as the fix will be merged to the upstream erlang.

[1] ppa:dgadomski/erlang

I am totally stuck with this issue. I disabled IPv6 via a Grub boot option.

When I try to set an IPv4 address for ERL_EPMD_ADDRESS it tells me that it can't be parsed. If I try an IPv6 address (like comment #6 recommends) it tells me "Address family not supported by protocol".

I tried Dariusz' Erlang repository but now I get "Address family not supported by protocol" for IPv4 and IPv6 addresses.

Daniel: can you please try the latest version available in my ppa [1]. It contains the latest approach taken upstream to solve this issue. Please provide your feedback regarding this. Thanks!

[1] ppa:dgadomski/erlang

Dariusz: I'm seeing the same issue, but running on Vivid, could you add packages for that to your repo so I could test your solution?

A build for Vivid is available in my ppa [1] for testing. I will appreciate any feedback. Thanks!

[1] ppa:dgadomski/erlang

hi guys,

please take a look at the date the bug was reported:
2014-09-25, status is auto-confirmed and prio is high.
Is there chance that this gets fixed before one year is over?
I would also argue the estimated number of unreported cases is much higher!
Greetings,
LR

@Dariusz: The package for Vivid works fine for me, thanks.

Running with 1:18.3-dfsg-1ubuntu3 on Xenial, the issue seems to have been fixed for me, can anyone confirm this?

Just to let you know about a possibly interesting edge case which *may* be related to this bug - if I use "ipv6.disable=1" to disable ipv6, "export ERL_EPMD_ADDRESS=127.0.0.1" works as expected, if I use "net.ipv6.conf.all.disable_ipv6 = 1" via sysctl to disable ipv6, I get "epmd: failed to bind socket".

Using RabbitMQ 3.5.7-1ubuntu0.16.04.1 on 16.04.

Tried the workaround from comment 6 but obviously that's unlikely to work with ipv6 disabled.

Additionally, using "net.ipv6.conf.lo.disable_ipv6 = 0" to enable ipv6 just for loopback works around the problem, and lsof -i does show epmd using ipv6 despite specifying only the ipv4 loopback in ERL_EPMD_ADDRESS.

lsof -i |grep epmd
epmd 30418 rabbitmq 3u IPv4 458312 0t0 TCP localhost:epmd (LISTEN)
epmd 30418 rabbitmq 4u IPv6 458313 0t0 TCP localhost:epmd (LISTEN)
epmd 30418 rabbitmq 6u IPv4 457617 0t0 TCP localhost:epmd->localhost:59565 (ESTABLISHED)
beam.smp 30476 rabbitmq 13u IPv4 459345 0t0 TCP localhost:59565->localhost:epmd (ESTABLISHED)