Re: Broken IPv6 / IPv4 configuration, or Gmail brokenness?
Celejar wrote:
> Hello,
>
> My Debian Sid system, including its networking system, has been
> working fine for a while. Recently, Gmail has not been working properly
> on the system: sending (via SMTP with SSL) times out, and receiving
> (via POP3 and IMAP) takes abnormally long. Today I finally made some
> efforts to understand what's going on. Here's what I know /
> understand / have been able to establish:
>
> 1) My ISP provides me with only IPv4, not IPv6.
>
> 2) Trying to send email through Gmail using "smtp.gmail.com", via
> Sylpheed and Swaks, times out without getting anywhere. For example:
>
> $ swaks -t celejar@gmail.com -s smtp.gmail.com:587 -tls -a LOGIN
> Username: celejar
> Password: ********
> === Trying smtp.gmail.com:587...
> *** Error connecting to smtp.gmail.com:587:
> *** IO::Socket::INET6: connect: timeout
>
> 3) Forcing the use of IPv4 fixes the timeout problem. In particular,
> both of the following work (in the second command, the IPv4 address is
> the one returned by "dig" and "host" for "smtp.gmail.com"):
>
> $ swaks -t celejar@gmail.com -4 -s smtp.gmail.com:587 -tls -a LOGIN
> $ swaks -t celejar@gmail.com -s 142.251.163.109:587 -tls -a LOGIN
>
> So, what's going on here? I suppose I don't really need IPv6 on my
> system, but everything I've read says that it should be left enabled and
> not disabled. Is something misconfigured on my system, is this a Gmail
> problem, or am I missing something else?
Your system expects to be able to use IPv4 and IPv6. Google
handles both. Your ISP does not. DNS returns both IPv4 A records
and IPv6 AAAA records for smtp.gmail.com.
In this particular case, you should change your system
preference to IPv4 first.
In /etc/gai.conf:
UNcomment
precedence ::ffff:0:0/96 100
and that should solve the issue immediately, at the cost of
making IPv6 unusable until you re-comment that.
-dsr-
Reply to: