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 cele...@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 cele...@gmail.com -4 -s smtp.gmail.com:587 -tls -a LOGIN > $ swaks -t cele...@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-
