Servus Philipp, Unfortunately the traceroute(6) results are both more or less random. Sometimes traceroute "hangs" a while, wherever, sometimes traceroute6. Sometimes traceroute is faster, sometimes traceroute6. Not reliable. Your MTU question, tried as adviced: Maximum size for IPv4 is 1466, and max size for IPv6 is 1444. Exceeding these values leads to a "ping: local error: Message too long, mtu=1492" in both cases. My Fritzbox says "Native IPv6", no tunnel, no underlying "IPv4 via DS-Lite". These are the default settings for ISP "Deutsche Telekom", VDSL-50. VINCENZO: Tried as adviced to test with FTP, installed pure-ftpd and opened VPS's ftp port in firewall. Maximum IPv4 speed was much slower (1.5-2 MB/sec) than other tests, maybe temporary issue or virtualization. But again: IPv6 was MUCH slower than IPv4. Am 07.11.18 um 20:57 schrieb Philipp Marek: > >> first post to list, hopefully on-topic. Haven't found anything on the >> net, tried to ask at first in OpenSuse forums a >> while ago >> (https://forums.opensuse.org/showthread.php/533588-rsnapshot-rsync-massive-performance-decrease) >> and today >> opened a bug in OpenSuse's Bugzilla >> (https://bugzilla.opensuse.org/show_bug.cgi?id=1115075) >> >> As written in bug report, as general network issues could be excluded, >> any hints where to start, how to narrow down if >> this is a specific openssh issue or something else? > > Your IPv6 _route_ has 3 times the latency: > > $ time /usr/sbin/traceroute vserver.domain.tld > ... > 7 domain.tld (IPv4) 26.002 ms !X 24.859 ms !X 25.230 ms !X > > $ time /usr/sbin/traceroute6 vserver.domain.tld > ... > 8 domain.tld (IPv6) 80.430 ms !X 79.301 ms !X 80.444 ms !X > > The big time waster seems to be this link: > 6 nug-d-i40-v6.telia.net (2001:2000:3018:8d::1) 32.046 ms 23.850 ms 24.097 ms > 7 contabo-ic-305268-ffm-b11.c.telia.net (2001:2000:3080:953::2) 74.829 ms 77.704 ms 78.066 ms > > I'll now speculate that you might as well have some MTU mismatches, > meaning that packages have to get split up along the way, further > slowing down your connection. > > Do you have native IPv6 all the way, or is there an 6-in-4 tunnel > inbetween (from the fritzbox on)? > > Please try > # ping -M do -s <size> <ip> > for sizes between 1300 and 1500 and find the largest (even) packet size > that still works, and then do the same with ping6 as well. > > Also note whether some packetsize works, but just larger ones vanish > along the way. _______________________________________________ openssh-unix-dev mailing list openssh-unix-dev@xxxxxxxxxxx https://lists.mindrot.org/mailman/listinfo/openssh-unix-dev
