CentOS - Nov 2016 - Need help getting two NICs to work on CentOS 7

Hello there,

What is the hypervisor that hosts the VM? What does ifconfig show on it?

Boris.

On Mon, Nov 7, 2016 at 4:36 PM, Gordon Messmer <gordon.messmer at
gmail.com>
wrote:
> On 11/06/2016 11:00 PM, Sean Son wrote:
>
>> How do I
>> configure the networking so that both IPs are pingable and the VM is
>> reachable via both IPs?
>>
>
>
> You need one rule file per interface, which directs traffic out the
> appropriate interface based on the source address of the packet:
>
> https://blogs.oracle.com/networking/entry/advance_routing_for_multi_homed
>
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> CentOS at centos.org
> https://lists.centos.org/mailman/listinfo/centos
>

On Tue, Nov 8, 2016 at 8:02 AM, Boris Epstein <borepstein at gmail.com>
wrote:
> Hello there,
>
> What is the hypervisor that hosts the VM? What does ifconfig show on it?
>
> Boris.
>
> On Mon, Nov 7, 2016 at 4:36 PM, Gordon Messmer <gordon.messmer at
gmail.com>
> wrote:
>
> > On 11/06/2016 11:00 PM, Sean Son wrote:
> >
> >> How do I
> >> configure the networking so that both IPs are pingable and the VM
is
> >> reachable via both IPs?
> >>
> >
> >
> > You need one rule file per interface, which directs traffic out the
> > appropriate interface based on the source address of the packet:
> >
> > https://blogs.oracle.com/networking/entry/advance_
> routing_for_multi_homed
> >
> > _______________________________________________
> > CentOS mailing list
> > CentOS at centos.org
> > https://lists.centos.org/mailman/listinfo/centos
> >
> _______________________________________________
> CentOS mailing list
> CentOS at centos.org
> https://lists.centos.org/mailman/listinfo/centos
>

Hello all

Thank you for the replies.  I ran into  some issues with the policy based
routing which I will explain in a few.  First off to answer each one of
your questions:

Digimer: No I didnt take a look at IPTables

Peter Brady: Thank you for the example, I tried that but it failed and I
will explain in a minute.

Frank Cox : That works but how do I make it persistent across reboots?

Boris Epstein:  I am using Hyper-V and its getting annoying lol


Ok so here is how I have set everything up:

my /etc/iproute2/rt_tables:


#
# reserved values
#
255     local
254     main
253     default
0       unspec
#
# local
#
#1      inr.ruhep
300 NIC1
310 NIC2

my /etc/sysconfig/network-scripts/route-eth0 file:

168.87.147.0/24 dev eth0 table 300
default via 168.87.147.1 dev eth0 table 300

/etc/sysconfig/network-scripts/route-eth1 file:

10.20.50.0/24 dev eth1 table 310
default via 10.20.50.1 dev eth1 table 310

My /etc/sysconfig/network-scripts/rule-eth0:

from 168.87.147.33/32 table 300
to 168.87.147.33 table 300

My /etc/sysconfig/network-scripts/rule-eth1:

from 10.20.50.90/32 table 310
to 10.20.50.90 table 310


now after implementing this and restarting NetworkManager,  when I run 'ip
rule list', I get the following:

0:      from all lookup local
32764:  from all to 10.20.50.90 lookup NIC2
32765:  from 10.20.50.90 lookup NIC2
32766:  from all lookup main
32767:  from all lookup default


and when i run 'ip route' , i get the following:

default via 168.87.147.1 dev eth0  proto static  metric 1024
10.20.50.0/24 dev eth1  proto kernel  scope link  src 10.20.50.90
168.87.147.0/24 dev eth0  proto kernel  scope link  src 168.87.147.33



yet when I try to ping from another server to 10.20.50.90 it will not ping
at all. Also, whenever I reboot the VM, eth1 switches over to DHCP and I
lose my IP configuration. After I reset the IP Configuration back to Manual
and reenter the IP, Centos creates a new interface file called
ifcfg-Wired_Connection-1 and places the IP configuration for the interface
into that file. Both virtual NICs are set to Static Mac Addresses, so I
dont know why it keeps creating another interface file.  Any ideas on what
I am doing wrong here? All help is greatly appreciated!


Thanks!

On 11/14/2016 12:47 PM, Sean Son wrote:
> Any ideas on what
> I am doing wrong here?

Nothing obvious.  Since your interfaces have static configurations, I'd 
suggest turning off NetworkManager and turning on the "network"
service
to determine whether or not that works correctly after a reboot.

Assuming it does, fixing the issue might be as simple as getting 
NetworkManager to not rename one interface to "wired connection 1".