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Help needed w/ vz networking: What terminology am I looking for? [message #14707]

Fri, 06 July 2007 18:08

cheuschober
Messages: 5
Registered: April 2007
Location: NY,NY

Junior Member

Hi. Complete and under networking administration 'newb' but I do want to learn. Problem is, sometimes I don't know what the proper terms to google are...

Here's the situation:

I have a machine with two interfaces (eth0,eth1). eth0 is reserved for non-ve traffic, eth1 is reserved for ve traffic only. (I followed http://wiki.openvz.org/Multiple_Network_Interfaces_And_ARP_F lux regarding that)

The lan domain is 'sleepy' (172.16.192.0/24) behind a pfsense firewall/router.

I would like the ve's to have their own domain 'dopey' (172.16.91.0/24) but be able to have dns resolution across the whole network in both directions. (eg .sleepy machines can ping dns names of .dopey machines and visa versa)

Right now I cannot, for the life of me, figure out how to get traffic routed across much less set up dns resolution unless I set up the ve's on the primary lan domain in which case everything works without the need for configuration. I'm going to guess this has to do with iptables but beyond that I'm lost. Is this SNAT? DNAT? Both? Something else entirely?

First, I guess I should ask if this is even possible. If it is what specifically do I need to research to get this working?

Many thanks and regards.

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Re: Help needed w/ vz networking: What terminology am I looking for? [message #14709 is a reply to message #14707]

Fri, 06 July 2007 21:00

dim
Messages: 344
Registered: August 2005

Senior Member

DNS and IP connectivity are rather orthogonal. So, let's figure 2 issues:
1) you want that VEs with IPs from 172.16.91.0/24 pool could ping nodes with IPs from 172.16.192.0/24 pool and vice versa;

2) you want that there will be transparent DNS configuration, such that you may avoid using direct IPs, but use DNS names instead.

In order to resolve first issue, one need to know configuration of IP protocol on the node, where VEs run ('ip a l', 'ip r l', 'iptables-save' commands). And only when first issue will be resolved, than one could check the second one.

http://static.openvz.org/openvz_userbar_en.gif

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Re: Help needed w/ vz networking: What terminology am I looking for? [message #14712 is a reply to message #14709]

Sat, 07 July 2007 03:24

cheuschober
Messages: 5
Registered: April 2007
Location: NY,NY

Junior Member

Hi Dim.

Thank you for the response.

I ran the commands from inside the ve, as you suggested, but I guess I'm not certain what I'm supposed to be looking for.

root@test:~# ip a l
1: lo: <LOOPBACK,UP,10000> mtu 16436 qdisc noqueue 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
3: venet0: <BROADCAST,POINTOPOINT,NOARP,UP,10000> mtu 1500 qdisc noqueue 
    link/void 
    inet 127.0.0.1/32 scope host venet0
    inet 172.16.91.102/32 scope global venet0:0
root@test:~#  ip r l
192.0.2.1 dev venet0  scope link 
default via 192.0.2.1 dev venet0 
root@test:~# iptables-save 
# Generated by iptables-save v1.3.6 on Sat Jul  7 03:27:47 2007
*mangle
:PREROUTING ACCEPT [178:16453]
:INPUT ACCEPT [178:16453]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [126:17277]
:POSTROUTING ACCEPT [126:17277]
COMMIT
# Completed on Sat Jul  7 03:27:47 2007
# Generated by iptables-save v1.3.6 on Sat Jul  7 03:27:47 2007
*filter
:INPUT ACCEPT [186:16869]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [135:18385]
COMMIT
# Completed on Sat Jul  7 03:27:47 2007

Is it the ve or the hn I should be concerned with?

Regards and thanks.

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Re: Help needed w/ vz networking: What terminology am I looking for? [message #14734 is a reply to message #14707]

Mon, 09 July 2007 10:30

n00b_admin
Messages: 77
Registered: July 2006
Location: Romania

Member

you must run the commands on the hn not the ve's since the hn is doing all the packet routing.

You need to explain in more detail your network configuration because i didn't understood correctly what you have there...

So, you have ONE HN.

TWO subnets: 172.16.91.0/24 and 172.16.192.0/24 (used only by the ve's ?)

TWO network cards on the HN. What address is each interface using ?

After that you paste the output from the commands,run on the HN, Dim told you.

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Re: Help needed w/ vz networking: What terminology am I looking for? [message #14735 is a reply to message #14712]

Mon, 09 July 2007 10:36

dim
Messages: 344
Registered: August 2005

Senior Member

Please, post also output of above commands from HN.

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