CentOS 5 Networking :: VLAN And Gateway Outside Of Subnet?
Jan 12, 2011
My company hosts five Servers with CentOS 5 installed in a Data Center. The Data Center assigns a VLAN to each customer so that they can organize customers and also count traffic. The VLAN assigned to my company is in the form 62.103.X.X with a subnet mask 255.255.255.240 so the IPs that we can use in our Servers are 13. The first IP in the VLAN (for example 62.103.1.1) is the Gateway and the rest, that are calculated from the subnet mask, are assigned to servers(62.103.1.2 up to 62.103.1.14).
The problem I have is that we have run out of IPs in our VLAN. We have used all IPs and we want some more. The Data Center can assign new IPs but not grow our VLAN IPs by expanding the subnet mask. So they gave us a new VLAN with some IPs (for example 62.104.X.X with a subnet mask 255.255.255.192) They told me that I had to use as gateway the gateway of the first VLAN 62.103.1.1 and assign the new IPs as usual. So I assigned to one of the CentOS 5 servers the IP 62.104.1.2 and set the gateway to 62.103.1.1. Unfortunately this did not work and we could not establish connectivity to the Internet.Is it possible to assign a gateway outside of the IPs that are in the subnet? Could it be a problem with the VLAN setup by the Data Center?
I have TWO L3 + router switch (say switch1 and switch2). I created VLAN100 with VLAN ID 100 in both the switches. I created router 192.168.1.1/24 in Switch1. I created router 192.168.2.1/24 in Switch2. Switch1 is connected with 1.x/24 PCs. PCs are configured with 1.1 gateway. Switch2 is connected with 2.x/24 PCs. PCs are configured with 2.1 gateway. Both Switch1 and switch2 are connected by a trunk to carry VLAN100 data.
1)I have few PCs of 1.x connected to say Switch1 Is it possible for PC with IP 192.168.1.100(x) to ping PC with IP 192.168.2.100(y)?What are the configuration required in both switches to make them communicate ? All the device in both the subnets should ping/communicate with each other.
2)Move PC (192.168.1.100) to switch2. Move PC (192.168.2.100)to switch1.What will happen when PC(1.100) ping (2.100) and vice versa?What will happen when PC(say 1.80 in switch1) pings PC (say 1.100 in switch2) and vice versa? What will happen when PC(say 1.80 in switch1) pings PC (say 2.100 in switch1) and vice versa?
I am running RHEL 5.3 on a blade server w/ 2 NICs that are bonded. I have 2 VLANs that I am trying to configure. I have created the network-scripts ifcfg-bond0.<vlan#>. I can ping the device but the gateway won't ping. I am in console mode so cutting and pasting output doesn't work.
I've rent a server from a Germany data center,They use a single IP as their gateway that is not in range of my servers IP,Strangly server is working well and when I use 'route -n' command the gateway which is in other subnet appears properly./etc/sysconfig/network contains no gateway IP and I don't know how they set the default gateway while after reboot the gateway is the same, also the IP is static and there's now DHCP.I need to know how they did it so I can do the same on my VPSes.
I'm trying to setup routes for a gateway that resides on a different subnet. Our ISP leased us a block of IPs and told us to route through the current gateway, which is on a different subnet than our current block of addresses. To test, I've enabled one of the new addresses on one of the existing machines, which works. That machine has an address on the same subnet as the gateway, however.
The gateway address is 24.111.1.177 One of the new addresses I'm trying to use is 96.2.192.130, netmask= 255.255.255.240, broadcast= 96.2.192.143 Obviously, I can't just specify that gateway in /etc/network/interfaces without some routing, which is where the trouble I'm having is. The machine I'm trying to set this up on is part of 2 networks - one internal, on two different NICs.
I am trying to provide dynamic IP addresses for devices that are on a different VLAN (101). The server is currently providing 172.17.x.x/16 range for its own VLAN (417). My server is RHEL4 and DHCPD is version 3.0.1. The core switch (Cisco 3750) is configured with ip-helper on VLAN 101 interfacce. Here is my dhcpd.conf file:
I'm trying to setup a Asterisk box with two NIC's. The idea is that one NIC connects to the LAN on VLAN2 (for internal voice) and the other to the SIP trunk on my ISP's Cisco 1811, configured for VLAN3.
Some info: The Cisco's VLAN1 + 2 are available on my switch. VLAN1 = 10.105.44.x with gateway .254 (the Cisco). VLAN2 = 10.106.45.x with gateway .254 (the Cisco). The Cisco's VLAN3 is available on only a single port on de Cisco, connected to one of de NIC's of the Asterisk box, eth1, with IP 10.106.46.1 and gateway .254 (the Cisco). The other NIC, eth0, is connected to the switch, on a port setup for VLAN2.
So, what I'm trying to achieve: Use eth1 tagged with VLAN3 to connect to the SIP trunk. (I could do this with a static route because my provider has a fixed IP to connect to) Use eth0 for all other traffic.
Here are some config files I've setup so far (I'm stuck on connecting to the SIP provider):
I need to set a NAC (PacketFence) system (CentOS 5.5), i would like to set in my case eth0 to work with several different VLAN'S i created ifcfg-eth0.2 copied from orginal ifcfg-eth0 and changed the ip and append VLAN=yes but when i am triyng to load ifcfg-eth0.2 i get error
my ifcfg-eth0 goes as follow
# Intel Corporation 82578DM Gigabit Network Connection # Normal VLAN Lan adapter (Managment)(On-boad 1st NIC) DEVICE=eth0
I have a motherboard which has 4 x 1Gbps Ethernet controllers. I would like to use it as a Gateway for my home network. I have a static IP from my ISP which I can use to configure eth0 (I haven't done it yet as the LE-565 is currently sitting behind my Netgear router until I've got DHCP working). I would like to use eth1, eth2 and eth3 for my LAN. How do I set things up so that DHCP is handing out IP addresses on the same subnet (192.168.0.0/24) on all three interfaces?
P.S. I think what I'm asking is: how do I combine all 3 interfaces to behave like a switch (ie. just like my Netgear router)?
I installed Redhat Enterprise linux server5. it has two LAN card and two subnet connected to these two LAN card. i can browse network from these two network easily. But i created VLAN on one network card.Now i cant browse network from these VLAN subnet.
I am using centOS 5.0. After I change from DHCP to static IP address, I cannot ping hosts on the same subnet. The error message says destination host unreachable. Before I made the changes I was able to ping and now even I change it back to DHCP I still cannot ping with the same destination host unreachable message. The centOS is running on VMware on a Windows host.
After pinging 192.168.0.106 (106 is on and other host can ping it), arp -a shows ? (192.168.0.106) at <incomplete> on eth0 I tried different ways by disabling the firewall and and disabling SE protection. No Luck.
I will try to explain a bit first about my network typology: I have one cent os 5.5 machine with 2 nics - external one 86.x.x.122 and internal one with 2 IPs: 192.168.1.1 and 89.x.x.121. The ideea is that I have a public subnet (86.x.x.120/29) of IPs which are routable only through 86.x.x.122 so I have a webserver hosted on a different machine with the IP of 89.x.x.122 and GW 89.x.x.121 - everything works perfectly fine, except that I cannot access from the internal network 192.168.1.0 / 24 the so called DMZ (roughly) - the 89.x.x.122.
What really makes me crazy is that I setup the IPtables rules correctly because I can access the webserver from the outside world but I cannot accessit from the internal network...
what I'm missing - why the 192.168.1.0/24 cannot see the 89.x.x.122 machine... What IPtables rules should I add?
I've got a bit of a question. My network is laid out like this:
The role assignments are thus:
Firewall - sorts out the passing through to the 3 different networks, and acts as the traffic proxy. Windows 2003 server - Does Active Directory and DNS CentOS server - FTP and DHCP
Now, my problem is I need the CentOS server to be able to assign IP address to both networks, however, the CentOS server can *ONLY* be connected via the one interface to the firewall. It needs to assign the Windows 2003 server and the eth0 of the firewall an IP address via static DHCP, but it also needs to able to assign the clients dynamically via any address in the 10.23.1.0/24 range. I was thinking that I would be able to create static only assignments for the servers via their MAC addresses, and only have 1 dynamically assignable entry for the clients, and then get the firewall to allow ports 67 and 68 to flow freely between eth0 and eth1, but I wasn't entirely sure of the best way to do all this.
Recently my motherboard went out, I replaced it and booted centos 5. All went well except sound, video tuners and netoworking. The sound I re-configured, and have gotten tuners working but I am running into trouble with the new network card. The networking setup is;
DSL wireless router/modem IP 192.168.0.1 connected to XP computer through WIFI IP 192.168.0.3. all set to subnetmask 255.255.255.0 and with DNS servers 192.168.0.1 and 205.171.3.25 the XP computer is the only one that supports my wifi card. On wired LAN I share that connection to 4 devices. 3/4 work well, my cent os 5 box will not connect. here are the lan settings:
win xp: IP 192.168.0.60 255.255.255.0 mac 8.6: IP 192.168.0.34 255.255.255.0 blueray: IP 192.168.0.65 255.255.255.0
I have a requirement of switch between wireless network with a single wireless device. First it should be switched to adhoc mode and then after sometime switch to infrastructure mode to establish internet connection. Everything works fine except the gateway settings.
I have used: system("route add default gw x.x.x.x dev wlan0") to set the gateway, where x.x.x.x is gatewayip address. I have used this whenever switching happens in addition to ifconfig command to set the ip address and netmask. But this is not setting the gateway ip address. How to set gateway IP address?
System details below OS :CentoS 5.3 Kernel :2.6.18
And I'm currently working on a new CentOS 5 install I've made on a computer I've got.. So I'm now trying to get that computer to reach my home network through one of my other computers, which have got XP installed. I've configured the XP computer to act as a gateway from one network card to another, and It works with another XP pc, but no luck with my CentOS 5. I used this link [URL] And I configured the correct network card.
So.. the IP of the XP machine is 192.168.1.70, which I have set as a static. So that the CentOS will find it. And I've connected the (fully working) network cable correctly.
What do I have to do?
I have configured the CentOS to recieve an IP dynamically. (dhcp).. Might that be the problem? (well.. one of the problems.. I've tried to set it to static.. ...?)
Is there more to it than this? I mean when I'm working on communication through an XP machine... ?
I posted it on another forum, but could not get response,So I have this cenOS, Ubuntu and windows operating system running on virtual machines.Now I gave them manual ip address, both ubuntu and windows machines can ping the default gateway, but not the CentOS.It should forward 0.0.0.0. to my cisco router address(192.168.5.254),
The install actually seemed to go pretty smoothlyIt's a dell pentium4 with 128mbyes it installed textuallyI start the gui with 'startx'but the question I have is for the more experienced CentOS people.when I login as rootI am trying to figure out how to get my machine onto the internet.I had figured the OS would have NO problem with a Linksys 10/100 pci cardsince the OS has the latest drivers and all.The system reports the NIC as a "ADMtek NC100 ethernet" card (eth0)it also reports that the status is "ok"Now, I've seen the NIC when it's plugged into a hub (during the O/S install)and it DOES make the hub's light flicker when it tries to "talk" to it.but when I have it plugged into my Cable Modem (for internet) it's not doing anything.
During the install I SAW the NIC making the hub lights flicker... so I know the interface WAS doing "something".but nowwhen I go into the gui and I try the NetWork Admin , and I try to "activate" the card.Nothing.Am I NOT doing something that I SHOULD be doing?fconfig? (at the command line?) ifup? I would have thought I'd "activate" it with the gui ok...I'll keep poking around.I'm just a little surprised is all. Ubuntu 8.1 had no problem "discovering" and using a wireless Linksys cardTHIS operating system is even newer
I could not able to configure the default gateway ip address onto the system. i use the route command (" route add default gw 192.xxx.xxx.xxx eth0 ") to add a default gateway onto the routing table but it is "disappear" in the routing table when i had restart the service network.
the problem is that with the above configuration, i connected 3 linux boxes on the switch but non of them could connect with each other. when i did a ping, it says "destination unreachable"
what am i missing out here, and whats the fix?
i assigned static ip address to these boxes, also there's no router in this network by the way. i dont think i will need one either as all the machines in in the same vlan2.
I'm preparing to "follow" these directions which will make VirtualBox's networking behave like VMWare's "NAT" networking. Of course, these instructions are for a Ubuntu/Debian setup.
I am quite certain that I can write a script that'll do the equivalent steps on my Fedora 11 box -- which is acceptable to me. I would, however, like to know how to splice this stuff into NetworkManager and/or /etc/sysconfig/networking/devices/, to do this the "right" way.
The desired networking behavior: -VM's get assigned addresses via DHCP on a virtual network -VM's can talk to each other and to their physical host -VM traffic out to the 'real world' is NATted
