Arch Linux

Mike Dowling

Member

Registered: 2009-09-11

Posts: 7

IPv6 problem or ISP problem or perhaps an authentication problem, can

Since installing Arch64  on a new computer earlier this year, sending email and downloading it using fetchmail has taken several minutes.  Now, after installing subversion, the same thing happens when checking in changes.  I tried to find out what was happening by using strace, and, after an initial boost of output, it stops.  Here is a section from a fetchmail attempt:

munmap(0x7fad0fad2000, 4096)            = 0
socket(PF_INET, SOCK_DGRAM, IPPROTO_IP) = 4
connect(4, {sa_family=AF_INET, sin_port=htons(25), sin_addr=inet_addr("127.0.0.1")}, 16) = 0
getsockname(4, {sa_family=AF_INET, sin_port=htons(44521), sin_addr=inet_addr("127.0.0.1")}, [16]) = 0
close(4)                                = 0
socket(PF_INET6, SOCK_DGRAM, IPPROTO_IP) = 4
connect(4, {sa_family=AF_INET6, sin6_port=htons(25), inet_pton(AF_INET6, "::1", &sin6_addr), sin6_flowinfo=0, sin6_scope_id=0}, 28) = 0
getsockname(4, {sa_family=AF_INET6, sin6_port=htons(43376), inet_pton(AF_INET6, "::1", &sin6_addr), sin6_flowinfo=0, sin6_scope_id=0}, [28]) = 0
close(4)                                = 0
socket(PF_INET6, SOCK_STREAM, IPPROTO_TCP) = 4
setsockopt(4, SOL_SOCKET, SO_KEEPALIVE, [1], 4) = 0
connect(4, {sa_family=AF_INET6, sin6_port=htons(25), inet_pton(AF_INET6, "::1", &sin6_addr), sin6_flowinfo=0, sin6_scope_id=0}, 28

It stops on that last line.  To me, it looks as if it is trying to use IPv6, but it cannot.  It presumably times out after a while and then used IPv4, which works.

I checked if others were having similar problems; one answer is to have the following line in /etc/modprobe.d/modprobe.conf:

alias net-pf-10 off

but that did not help me.  Another suggestion was to turn off IPv6 on the router.  My router configuration claims that is turned off already.  I doubt it, though, as I definitely see IPv6 packets when using tcpdump, for example "neighbor advertisements".

So, is my Arch behaving correctly and my router badly, or is there anything I can do with Arch to stop it from attempting to use IPv6?

This could also be a problem with authentication.  Checking out with subversion is fast, but checking in, sending and receiving email all require authentication.  All other TCP/IP protocols work fine.

I would be very grateful for any suggestions.

Yours,

Mike Dowling

R00KIE

Forum Fellow

From: Between a computer and a chair

Registered: 2008-09-14

Posts: 4,734

Re: IPv6 problem or ISP problem or perhaps an authentication problem, can

To disable ipv6 you need to follow these steps described here:
https://wiki.archlinux.org/index.php/IPv6#Disable_IPv6

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R00KIE
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