Description:

On system startup, ip6tables sometimes fails to load. "systemctl status ip6tables" shows this message:

ip6tables.service - IPv6 Packet Filtering Framework
Loaded: loaded (/usr/lib/systemd/system/ip6tables.service; enabled)
Active: failed (Result: exit-code) since Mo 2014-04-21 10:58:09 CEST; 42s ago
Process: 419 ExecStart=/usr/bin/ip6tables-restore /etc/iptables/ip6tables.rules (code=exited, status=2)
Main PID: 419 (code=exited, status=2)

Apr 21 10:58:09 deltaflyer ip6tables-restore[419]: ip6tables-restore v1.4.21: Set ports doesn't exist.

After bootup, a simple "systemctl restart ip6tables" successfully loads the ip6tables ruleset (because the "ports" ipset exists at that point). In /usr/lib/systemd/system/ipset.service is a line "Before=iptables.service". I added a new line "Before=ip6tables.service", and after several reboots, the problem did not occur again. I'll attach a proposed patch for Arch's ipset.service unit file.

Additional info:
* package version: ipset 6.21.1-1
* patched file: /usr/lib/systemd/system/ipset.service


Steps to reproduce:
1. generate an ipset for ports
2. use ports set in iptables and ip6tables ruleset
3. restart machine
4. during bootup ip6tables sporadically fails to load due to missing Before= dependency