2

I just need to re-roure all user traffic directly to specified GW (different from the default one) bypass all VPN and other routing rules.

Lets start it from scratch (reboot the system), no interface configured, no firewalld deamon works, just a clean system without any iptables rules.

reboot

[root@localhost ~]# cat /etc/iproute2/rt_tables|wc -l
0

[root@localhost ~]# ifconfig -a
enp3s0: flags=4098<BROADCAST,MULTICAST>  mtu 1500
        ether xx:xx:xx:xx:xx:xx  txqueuelen 1000  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10<host>
        loop  txqueuelen 0  (Local Loopback)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

[root@localhost ~]# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface

[root@localhost ~]# ip rule
0:  from all lookup local 
32766:  from all lookup main 
32767:  from all lookup default 

[root@localhost ~]# ip route
[root@localhost ~]# ip route show table all
broadcast 127.0.0.0 dev lo  table local  proto kernel  scope link  src 127.0.0.1 
local 127.0.0.0/8 dev lo  table local  proto kernel  scope host  src 127.0.0.1 
local 127.0.0.1 dev lo  table local  proto kernel  scope host  src 127.0.0.1
broadcast 127.255.255.255 dev lo  table local  proto kernel  scope link  src 127.0.0.1 
unreachable default dev lo  table unspec  proto kernel  metric 4294967295  error -101
local ::1 dev lo  table local  proto none  metric 0 
unreachable default dev lo  table unspec  proto kernel  metric 4294967295  error -101
[root@localhost ~]# 

[root@localhost ~]# ifconfig enp3s0 192.168.77.8/24 up

[root@localhost ~]#  ip route
192.168.77.0/24 dev enp3s0  proto kernel  scope link  src 192.168.77.8 

[root@localhost ~]# ip route show table all
192.168.77.0/24 dev enp3s0  proto kernel  scope link  src 192.168.77.8 
broadcast 127.0.0.0 dev lo  table local  proto kernel  scope link  src 127.0.0.1 
local 127.0.0.0/8 dev lo  table local  proto kernel  scope host  src 127.0.0.1 
local 127.0.0.1 dev lo  table local  proto kernel  scope host  src 127.0.0.1 
broadcast 127.255.255.255 dev lo  table local  proto kernel  scope link  src 127.0.0.1 
broadcast 192.168.77.0 dev enp3s0  table local  proto kernel  scope link  src 192.168.77.8 
local 192.168.77.8 dev enp3s0  table local  proto kernel  scope host  src 192.168.77.8 
broadcast 192.168.77.xxx dev enp3s0  table local  proto kernel  scope link  src 192.168.77.8 
fe80::/64 dev enp3s0  proto kernel  metric 256 
unreachable default dev lo  table 0  proto kernel  metric 4294967295  error -101
local ::1 dev lo  table local  proto none  metric 0 
local fe80::f279:59ff:fe6c:7833 dev lo  table local  proto none  metric 0 
ff00::/8 dev enp3s0  table local  metric 256 
unreachable default dev lo  table 0  proto kernel  metric 4294967295  error -101

gw respond to us.
[root@localhost ~]# ping -c 1 192.168.77.150
PING 192.168.77.150 (192.168.77.150) 56(84) bytes of data.
64 bytes from 192.168.77.150: icmp_seq=1 ttl=64 time=0.388 ms
--- 192.168.77.150 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.388/0.388/0.388/0.000 ms


[root@localhost ~]# iptables -L -nv
Chain INPUT (policy ACCEPT 16 packets, 2011 bytes)
 pkts bytes target     prot opt in     out     source               destination         
Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         
Chain OUTPUT (policy ACCEPT 17 packets, 1966 bytes)
 pkts bytes target     prot opt in     out     source               destination         

[root@localhost ~]# iptables -L -nv -t nat
Chain PREROUTING (policy ACCEPT 1 packets, 125 bytes)
 pkts bytes target     prot opt in     out     source               destination         
Chain INPUT (policy ACCEPT 1 packets, 125 bytes)
 pkts bytes target     prot opt in     out     source               destination         
Chain OUTPUT (policy ACCEPT 3 packets, 241 bytes)
 pkts bytes target     prot opt in     out     source               destination         
Chain POSTROUTING (policy ACCEPT 3 packets, 241 bytes)
 pkts bytes target     prot opt in     out     source               destination         


[root@localhost ~]# telnet 8.8.8.8 53
Trying 8.8.8.8...
telnet: connect to address 8.8.8.8: Network is unreachable

[root@localhost ~]# iptables -I OUTPUT -m owner --uid-owner test1 -j MARK --set-mark 2

[test1@localhost ~]$ telnet 8.8.8.8 53
Trying 8.8.8.8...
telnet: connect to address 8.8.8.8: Network is unreachable

echo 2 novpn >> /etc/iproute2/rt_tables

[root@localhost ~]# echo 2 novpn >> /etc/iproute2/rt_tables
[root@localhost ~]# ip rule add fwmark 2 lookup novpn priority 2

[root@localhost ~]# ip rule
0:  from all lookup local 
2:  from all fwmark 0x2 lookup novpn 
32766:  from all lookup main 
32767:  from all lookup default 
[root@localhost ~]# ip route
192.168.77.0/24 dev enp3s0  proto kernel  scope link  src 192.168.77.8 
[root@localhost ~]# 

[root@localhost ~]# ip route add default via 192.168.77.150 dev enp3s0 table novpn

[test1@localhost ~]$ telnet 8.8.8.8 53
Trying 8.8.8.8...
telnet: connect to address 8.8.8.8: Network is unreachable
[test1@localhost ~]$ 


[root@localhost ~]# iptables -L -nv
Chain INPUT (policy ACCEPT 1 packets, 125 bytes)
 pkts bytes target     prot opt in     out     source               destination         
Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         
Chain OUTPUT (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         
    0     0 MARK       all  --  *      *       0.0.0.0/0            0.0.0.0/0            owner UID match 1007 MARK set 0x2
[root@localhost ~]# 

iptables rule stays unmatched, how to fix it? Guessing, ... looks like we need to define default gw #wow!

route add default gw 192.168.77.150

test it now

[root@localhost ~]# iptables -L -nv
Chain INPUT (policy ACCEPT 3 packets, 375 bytes)
 pkts bytes target     prot opt in     out     source               destination         
Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         
Chain OUTPUT (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         
    0     0 MARK       all  --  *      *       0.0.0.0/0            0.0.0.0/0            owner UID match 1007 MARK set 0x2

conunters not yet increased, it is OK.

[test1@localhost ~]$ telnet 8.8.8.8 53
Trying 8.8.8.8...
Connected to 8.8.8.8.
Escape character is '^]'.
Connection closed by foreign host.

conunters increased:

[root@localhost ~]# iptables -L -nv
Chain INPUT (policy ACCEPT 6 packets, 539 bytes)
 pkts bytes target     prot opt in     out     source               destination         
Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         
Chain OUTPUT (policy ACCEPT 3 packets, 164 bytes)
 pkts bytes target     prot opt in     out     source               destination         
    3   164 MARK       all  --  *      *       0.0.0.0/0            0.0.0.0/0            owner UID match 1007 MARK set 0x2


[root@localhost ~]# ip route del default via 192.168.77.150 dev enp3s0 table novpn
[root@localhost ~]# show route table novpn
(no output)
[root@localhost ~]# ip route add default via 192.168.77.33 dev enp3s0 table novpn #192.168.77.33 does not exists

[test1@localhost ~]$ telnet 8.8.8.8 53
Trying 8.8.8.8...
Connected to 8.8.8.8.
Escape character is '^]'.
Connection closed by foreign host.

! Should not to connect to 8.8.8.8, since 192.168.77.33 how GW does not exists.

So, the ip route rule don't work.

[root@localhost ~]# ip rule
0:  from all lookup local 
2:  from all fwmark 0x2 lookup novpn 
32766:  from all lookup main 
32767:  from all lookup default 
[root@localhost ~]# ip route show table novpn
default via 192.168.77.33 dev enp3s0 
[root@localhost ~]# ip route show table main|fgrep default
default via 192.168.77.150 dev enp3s0 

[root@localhost ~]# iptables -L OUTPUT -nv
Chain OUTPUT (policy ACCEPT 196 packets, 40014 bytes)
 pkts bytes target     prot opt in     out     source               destination         
    9   492 MARK       all  --  *      *       0.0.0.0/0            0.0.0.0/0            owner UID match 1007 MARK set 0x2

How to proper set up all per-user traffic via different GW? Thanks.

Fedora release 22 (Twenty Two)
Linux lain 4.1.7-200.fc22.i686+PAE #1 SMP Mon Sep 14 20:36:56 UTC 2015 i686 i686 i386 GNU/Linux
iproute-3.16.0-3.fc22.i686
iptables-1.4.21-14.fc22.i686
0

I think the iptables -I OUTPUT -m owner --uid-owner test1 -j MARK --set-mark 2 command should be iptables -t mangle -I PREROUTING -m owner --uid-owner test1 -j MARK --set-mark 2

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