On Mon, Apr 17, 2017 at 11:22:17PM +0200, Ludovic Courtès wrote:
> Leo Famulari <leo@famulari.name> skribis:
> 
> > On Sun, Apr 16, 2017 at 11:57:25AM +0200, Ludovic Courtès wrote:
> >> Leo Famulari <leo@famulari.name> skribis:
> >> >>               (uri (string-append "ftp://ftp.mutt.org/pub/mutt/mutt-"
> >> >>                                   version ".tar.gz"))
> >> >
> >> > I found that Guix's FTP client is having trouble with this URL. It hangs
> >> > until it times out; other clients like wget and Firefox work fine.
> >> 
> >> I can’t reproduce this problem with Guix master (‘guix download’) and
> >> Guile 2.2 or 2.0.  Do you have more details?
> >
> > Strace shows it hangs here:
> >
> > [pid  4066] connect(13, {sa_family=AF_INET6, sin6_port=htons(60512), inet_pton(AF_INET6, "2600:3402:200:227::2", &sin6_addr), sin6_flowinfo=htonl(0), sin6_scope_id=0}, 28
> >
> > When I disable IPv6, it works. I can use other FTP clients over IPv6 to
> > download this file.
> 
> And what does strace give for those other FTP clients?  The port number
> looks fishy.

I'm out of my depth, but here is what I believe is the relevant portion
of the strace output while using wget (full strace log attached):

connect(3, {sa_family=AF_INET, sin_port=htons(0), sin_addr=inet_addr("140.211.166.134")}, 16) = -1 ENETUNREACH (Network is unreachable)
close(3)                                = 0   
socket(AF_INET6, SOCK_DGRAM, IPPROTO_IP) = 3
connect(3, {sa_family=AF_INET6, sin6_port=htons(0), inet_pton(AF_INET6, "2600:3402:200:227::2", &sin6_addr), sin6_flowinfo=htonl(0), sin6_scope_id=0}, 28) = 0
getsockname(3, {sa_family=AF_INET6, sin6_port=htons(59772), inet_pton(AF_INET6, "2601:47:4101:9916:2d39:1eca:471f:95be", &sin6_addr), sin6_flowinfo=htonl(0), sin6_scope_id=0}, [28]) = 0
connect(3, {sa_family=AF_UNSPEC, sa_data="\0\0\0\0\0\0\0\0\0\0\0\0\0\0"}, 16) = 0
connect(3, {sa_family=AF_INET6, sin6_port=htons(0), inet_pton(AF_INET6, "2600:3404:200:237::2", &sin6_addr), sin6_flowinfo=htonl(0), sin6_scope_id=0}, 28) = 0
getsockname(3, {sa_family=AF_INET6, sin6_port=htons(33848), inet_pton(AF_INET6, "2601:47:4101:9916:2d39:1eca:471f:95be", &sin6_addr), sin6_flowinfo=htonl(0), sin6_scope_id=0}, [28]) = 0
connect(3, {sa_family=AF_UNSPEC, sa_data="\0\0\0\0\0\0\0\0\0\0\0\0\0\0"}, 16) = 0
connect(3, {sa_family=AF_INET6, sin6_port=htons(0), inet_pton(AF_INET6, "2605:bc80:3010::134", &sin6_addr), sin6_flowinfo=htonl(0), sin6_scope_id=0}, 28) = 0
getsockname(3, {sa_family=AF_INET6, sin6_port=htons(55724), inet_pton(AF_INET6, "2601:47:4101:9916:2d39:1eca:471f:95be", &sin6_addr), sin6_flowinfo=htonl(0), sin6_scope_id=0}, [28]) = 0