Running Ubuntu 12.10 on amd64.
I'm trying to set up different routing rules for a particular user. I understand that the right way to do this is to create a firewall rule that marks the packets for that user, and add a routing rule for that mark. Just to get testing going, I've added a rule that discards all packets as unreachable:
# ip rule 0: from all lookup local 32765: from all fwmark 0x1 unreachable 32766: from all lookup main 32767: from all lookup default
With this rule in place and all firewall chains in all tables empty and policy ACCEPT, I can still ping remote hosts just fine as any user.
If I then add a rule to mark all packets and try to ping Google, it fails as expected
# iptables -t mangle -F OUTPUT # iptables -t mangle -A OUTPUT -j MARK --set-mark 0x01 # ping www.google.com ping: unknown host www.google.com
If I restrict this rule to the VPN user, it seems to have no effect.
# iptables -t mangle -F OUTPUT # iptables -t mangle -A OUTPUT -j MARK --set-mark 0x01 -m owner --uid-owner vpn # sudo -u vpn ping www.google.com PING www.google.com (126.96.36.199) 56(84) bytes of data. 64 bytes from wg-in-f103.1e100.net (188.8.131.52): icmp_req=1 ttl=50 time=36.6 ms
But it appears that the mark is being set, because if I add a rule to drop these packets in the firewall, it works:
# iptables -t mangle -A OUTPUT -j DROP -m mark --mark 0x01 # sudo -u vpn ping www.google.com ping: unknown host www.google.com
What am I missing? Thanks!