home lab VMs problem

[marcromansky]

I am trying to duplicate what we did in class last night and I can't ping from nosmo to arwen. (192.168.1.2 -> 192.168.2.125)

nosmo has routes to the 192.168.2.0 net via a gateway at 172.30.4.107. This 107 is not pingable on my network. I am currently running elrong, nosmo, celebrian and arwen. The diagram we have looks like elrond should be .107 but we made it use dhcp and it's default gw is 172.30.4.1 (nosmo) How is nosmo supposed to get over to the 172.30.[32].0 nets?

Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
172.30.4.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1
192.168.3.0 172.30.4.107 255.255.255.0 UG 0 0 0 eth1
192.168.2.0 172.30.4.107 255.255.255.0 UG 0 0 0 eth1
192.168.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0

[Rich Simms]

[quote]nosmo has routes to the 192.168.2.0 net via a gateway at 172.30.4.107. This 107 is not pingable on my network. [/quote]

I'd first solve the Nosmo to Elrond ping problem. Check the following:

nosmo eth1 cabled to VMnet2
elrond eth0 cabled to VMnet2

nosmo eth1 is 172.30.4.1/24, verify with ifconfig
elrond eth0 is 172.30.4.107/24, default gw=172.30.4.1, verify with ifconfig, route -n

from nosmo, the ping to 172.30.4.107 should work after that

- Rich

[marcromansky]

I'm gonna bet that when I brought the VM into my system and "Created" a new mac address, it wiped out the static ip info and set it to dhcp. In one of my other posts I noted:
" BUT it seems to me that I should be able to ping google.com from elrond with the default snapshot since it uses dhcp"
I think this mystery is solved.





[quote="Rich Simms"][quote]nosmo has routes to the 192.168.2.0 net via a gateway at 172.30.4.107. This 107 is not pingable on my network. [/quote]

I'd first solve the Nosmo to Elrond ping problem. Check the following:

nosmo eth1 cabled to VMnet2
elrond eth0 cabled to VMnet2

nosmo eth1 is 172.30.4.1/24, verify with ifconfig
elrond eth0 is 172.30.4.107/24, default gw=172.30.4.1, verify with ifconfig, route -n

from nosmo, the ping to 172.30.4.107 should work after that

- Rich[/quote]

[marcromansky]

OK, so from nosmo I can get to elrond's 172.30.4.107, and I can get to celebrian's eth0, but I can't ping celebrian's eth1 192.168.2.125 interface. I have celebrian set for ipforwarding. I thought that I would be able to get from nosmo to celebrian via the 192.168.1.197 interface which would then forward to the 192.168.2.125 interface which would be on the same subnet as arwen. Anyone see something I am missing?

# Controls IP packet forwarding
net.ipv4.ip_forward = 1

celebrian's route -n looks like:

Destination Gateway Genmask Flags Metric Ref Use Iface
192.168.2.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1
192.168.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth1
0.0.0.0 192.168.1.1 0.0.0.0 UG 0 0 0 eth0

[marcromansky]

BTW which one of Celebrian's interfaces should be the default gw for arwen. I currently have it as the 192.168.2.125 (and of course ipforwarding is set in /etc/sysctl.conf)

[marcromansky]

more clues: pinging arwen from elrond

[root@elrond ~]# ping 192.168.2.123
PING 192.168.2.123 (192.168.2.123) 56(84) bytes of data.
From 172.30.4.1: icmp_seq=2 Redirect Host(New nexthop: 172.30.4.107)
From 172.30.4.1: icmp_seq=3 Redirect Host(New nexthop: 172.30.4.107)
From 172.30.4.1: icmp_seq=4 Redirect Host(New nexthop: 172.30.4.107)
From 172.30.4.1: icmp_seq=5 Redirect Host(New nexthop: 172.30.4.107)

[Rich Simms]

Default GW's must be on the same network as the host interface being configured.

Can you post your network diagram? Will help with troubleshooting.

I did Lab 3 using the diagram in the Lab module of Lesson 3 using:

172.30.4.0/24 (Bridge "hub") SHIRE
Nosmo (the real one) (.1)
Frodo eth0 (DHCP)
Elrond eth0 (static)

192.168.2.0/24 (VMnet3 "hub") RIVENDELL
Elrond eth1 (static)
Legolas eth0 (static)

192.168.3.0/24 (VMnet4 "hub") MORDOR
Legolas eth1 (static)
Sauron eth0 (static)

- Rich

[marcromansky]

OK, so I got it all straightened out. I dumped all the VMs, went back to the copy from school, reverted back to snapshot, and made sure I created a new MAC for each one. On my previous attempt I moved some, created some....


The problem was in a whole mash of issues:

1) when you create a new MAC for the VMs at home, some of the VMs default the inteface back to DHCP. SO, elrond's eth0 was not .107 as it needed to be.

2) in some of the /etc/sysconfig/network-scripts/ifcfg-ethx files, there was a MAC address which I may have left in there when I changed it from DHCP to static. This may or may not have been an old MAC address. I suspect the MAC address is put in there when you bring up the interface, if you Created a new MAC address then changed from DHCP to static, it is possible that it was the old one. Without testing carefully I don't know if it was causing problems or not, but I think it was.

3) there are a couple of things in the assignment that had to be changed to suit the home network, like the static route for the host machine and there was a typo that said 172.30.1 instead of 172.30.4... Maybe an extra credit project would be to clean up the doc. ?

anyway, this is put to rest so I can get on with the new lab assignement.

marc