I just recently narrowed down or observed that on a rather new (fresh) leap system (15.5, all updated, default repos, very simple, single gigabit ethernet pcie interface (realtek, onboard, gigabyte GA-P55-UD3 mainboard) the system becomes rather sluggish and networking stuff (only ssh-ing into the machine, some very simple things) is very unresponsive.

until i discovered that even simple things such as direkt ipv6 pings onto ipv6 addresses fail and all packets become lost or never get replied.

ipv4 works normal.

whole network is a simple LAN with a normal soho gateway/home-router (fritzbox, in germany, deutsche telekom fibre provider consumer grade).

yast2 shows dhcp4 on the eth0, but i tried having both dhcp4 and dhcp6 enabled to acquire  the machines ip settings / assignments. or via neighbor announcement or what this stuff is called for ip6. either way, after less than a day of uptime of this leap 15.5 machine, the ipv6 stack seems to become non-working.


once the ipv6 layer is broken I have situations such as this:
--------

ping 2001:4860:4860::8844
PING 2001:4860:4860::8844(2001:4860:4860::8844) 56 data bytes


^C
--- 2001:4860:4860::8844 ping statistics ---
323 packets transmitted, 0 received, 100% packet loss, time 329725ms

-------------


/sbin/lspci  | grep -i net
03:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 03)


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i am not very fluent with systemd, so I used rcnetwork to reset the network stack or recycle it, and after this command, ipv6 works normal again as well.

> sudo rcnetwork restart

fixes the stuff. only to again fail after less than a day, I couldnt narrow this down to a more precise time span. maybe completely random.

any ideas?
thanks.