Routing
RHEL9
Use nmtui. Select connection you want to configure routing for, and select 'Routing'. Click <Edit...>. For example to route traffic from clonfarm21sro/129.57.69.11 to anything on subnet 129.57.177.0/25 through gateway 129.57.69.1, choose clonfarm21sro and set following:
Destination/Prefix: 129.57.177/0/25 Next hop: 129.57.69.1
Select following options:
[X] Never use this network for default route [X] Ignore automatically obtained routes [X] Ignore automatically obtained DNS parameters
After saving and exiting 'nmtui', restart connection:
nmcli connection down <connection> nmcli connection up <connection>
Check routing table with command ip route.
To check actual route to the machines on 177, use traceroute connamd, for example:
clonfarm21> traceroute ejfat-fs-daq traceroute to ejfat-fs-daq (129.57.177.7), 30 hops max, 60 byte packets 1 gw-69.jlab.org (129.57.69.1) 0.451 ms 0.438 ms 0.431 ms 2 * * * 3 * ejfat-fs-daq.jlab.org (129.57.177.7) 0.135 ms 0.129 ms
Solaris
Routing can be checked by command:
netstat -nr
To check traffic for example on 'e1000g1' interface type following command, it will show every 2 seconds:
netstat -I e1000g1 -i 2
For example on clondaq2 it shows following:
Routing Table: IPv4 Destination Gateway Flags Ref Use Interface -------------------- -------------------- ----- ----- ------ --------- 129.57.68.0 129.57.68.24 U 1 6 e1000g1 129.57.69.0 129.57.69.202 U 1 3 e1000g2 129.57.167.0 129.57.167.109 U 1 546 e1000g0 129.57.16.0 129.57.68.100 UG 1 4 224.0.0.0 129.57.167.109 U 1 0 e1000g0 default 129.57.167.99 UG 1 356 127.0.0.1 127.0.0.1 UH 5 180 lo0
In that example traffic was routed to subnet 16 to serve SILO. It was achieved by script /etc/rc3.d/S99manualroute with following contents:
#!/sbin/sh
#
# This script adds a manual route to force traffic to the 16 net
# out the NIC that is on the 129.57.68.x lan.
# - P. Letta 04/06/2006
case "$1" in
start)
/usr/sbin/route add -net 129.57.16.0 -netmask 255.255.252.0 129.57.68.100
/usr/sbin/route add -net 129.57.166.0 -netmask 255.255.255.0 129.57.68.100
;;
stop)
;;
*)
echo "Usage: $0 { start }"
exit 1
;;
esac
exit 0
NOTE: to delete routing setting for example do following:
/usr/sbin/route delete -net 129.57.166.0 -netmask 255.255.255.0 129.57.68.100
Linux:
clondb1
Add 2 files to /etc/sysconfig/network-scripts/ directory:
route-eth0:
GATEWAY0=129.57.167.99 NETMASK0=0.0.0.0 ADDRESS0=0.0.0.0
route-eth1:
GATEWAY1=129.57.68.100 NETMASK1=255.255.255.0 ADDRESS1=129.67.68.0
Restart network by service network restart. Command route must show following:
[root@clondb1 ~]# route Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 129.57.68.0 * 255.255.255.0 U 0 0 0 eth1 129.57.167.0 * 255.255.255.0 U 0 0 0 eth0 169.254.0.0 * 255.255.0.0 U 0 0 0 eth1 default hallb-gp.jlab.o 0.0.0.0 UG 0 0 0 eth0 [root@clondb1 ~]#
from web
If you know there is always going to be a permanent route for a destination then a static route can be a viable option.To add a persistent static route in Redhat Enterprise Linux create a file called route-<int>X in the directory
/etc/sysconfig/network-scripts/
where <int> is the interface number and X is the interface number. As you would expect, these are specified in seperate file for each of the available interface. Example:
/etc/sysconfig/network-scripts/route-eth0 /etc/sysconfig/network-scripts/route-eth1
Every entry or a route has three entities as follows:
GATEWAY<N>=xxx.xxx.xxx.xxx NETMASK<N>=yyy.yyy.yyy.yyy ADDRESS<N>=zzz.zzz.zzz.zzz
As the names implies, they are the gateway IP, Netmask and the IP/Network Address. Note the <N> next to each of the three entities. This number defines the route entry number and should be the same on all the entities. Example:
GATEWAY0=192.168.1.1 NETMASK0=255.255.255.0 ADDRESS0=10.10.10.0
GATEWAY1=192.168.1.1 NETMASK1=255.255.255.0 ADDRESS1=20.20.20.2
A sample file /etc/sysconfig/static-routes is available for your reference.
Once the file is created, restart the network service as follows:
# service network restart
To view the routes type
# route Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 192.168.1.0 * 255.255.255.0 U 0 0 0 eth0 192.168.2.0 * 255.255.255.0 U 0 0 0 eth1 10.10.10.0 * 255.255.255.0 U 0 0 0 eth0 20.20.20.2 * 255.255.255.0 U 0 0 0 eth0 169.254.0.0 * 255.255.0.0 U 0 0 0 eth1 default 192.168.1.1 0.0.0.0 UG 0 0 0 eth0
or
# ip route show 192.168.1.0/24 dev eth0 proto kernel scope link src 192.168.1.1 192.168.2.0/24 dev eth1 proto kernel scope link src 192.168.2.1 10.10.10.0/24 via 192.168.1.1 dev eth0 20.20.20.2/24 via 192.168.1.1 dev eth0 default via 192.168.1.1 dev eth0
To dynamically add a route, try the folowing:
Syntax: # ip route add <Net/IP>/<Mask> via <Gateway> dev <Int>X
Example: # ip route add 10.10.10.0/24 via 192.168.1.1 dev eth0
or
Syntax: # route add [-net|-host] <IP/Net> netmask <Mask> gw <Gateway IP> dev <Int>X
Example: # route add -net 10.10.10.0 netmask 255.255.255.0 gw 192.168.1.1 dev eth0
advise
Specify two gateways for two network destinations: (i.e. one external, one internal private network. Two routers/gateways will be specified.)
Add internet gateway as before: route add default gw 201.51.31.1 eth0 Add second private network: route add -net 10.0.0.0 netmask 255.0.0.0 gw 192.168.10.254 eth0
See more here.