Ubuntu Networking :: Can't Reach Any Host With Either Interface
Mar 30, 2010
I am running a server that needs both a wired and wireless connection with static IPs, with wireless as the default link. I'm using the SMCWUSB-G for wireless. I was running Debian for a while and had some routing tables set up as in [URL].... Everything worked until I recently switched to Ubuntu Server 9.10. After the switch a weird behavior showed up: if wlan0 is down, eth0 works fine. But if wlan0 is up, I can't reach any host with either interface (even nameservers or the gateway I am supposedly connected to). ifconfig indicates that nothing is wrong. It's really not clear what is causing this problem. It seems like something has to be wrong with both the wireless hardware/drivers and the routing tables in order for turning wireless on to interfere with "ping -Ieth0".
I've set up ubuntu server 10.04 x64 with kvm and bridged networking and installed win server 2008 as a guest os. The guest os has full access to the network including lan/wan but the host os can only reach my lan and not the wan. This is true even when the guest machine is powered off?I have to admit that my knowledge of networking, particularly with respect to linux is very flakey but surely if the guest has internet access this should also apply to the host? My only suggestion is an issue with mac addresses but i don't know where to start. Has anybody ran into this problem before?
Recently I've been unable to load web pages, hosted on my Ubuntu Guest in Apache, from my OSX Host. In fact, I can no longer even ping the Guest OS from the Host. In the past, when I did ifconfig on the Guest, I got an IP of 10.0.1.n. Now I'm getting 10.0.2.15--the default NAT Address. The thing is, I didn't change any settings recently. What I did do is run software update for OSX, Ubuntu, and updated VirtBox.
why I can no longer access my Guest OS from my Host? I spent hours on this last night, to no avail. What would cause the Guest IP to change from 10.0.1.n to 10.0.2.15? As I say, I manually made no config changes.
This is a RHEL 5.4 install. I did a fairly routine install setting up a static IP address of 10.5.96.10, a subnet mask of 255.255.254.0, and a gateway of 10.5.96.1 with the standard DNS setup for this network. These are all standard network setting for this network and otherwise work fine on other systems. The IP, gateway, and subnetmask all appear correctly on all relevant configuration files. This server can not ping any other system on the network and can not ping its default gateway. No other systems can ping this one either. Also this system can not ping "localhost" or its own hostname. The hosts file contains the line:
[code]...
I can ping 127.0.0.1 and 10.5.96.10 and it works fine. Also the firewall is disabled. I know I probably can't get a straight forward fix with the information I have on hand right now, I'm more of a Debian guy, so there might be some Red Hat intricacies I'm not familiar with. I think I had a CentOS install some months back that had this issue and I don't remember how I fixed it, or if I even did. I might have just replaced it with Debian. That's unfortunately not an option this time around since it's not my box.
I have a linux router with 2 physical ISPs and a VPN tunnel that all my traffic passes through. I would like to setup a rule to redirect all traffic from one internal IP address (10.0.0.x) through the physical link only. My current script is as follows.
I have set up my guest OS in VirtualBox so that it has a static ip and is using a bridged adapter. As a result, I can see the webserver that's hosted in guest from my host OS's web browser. However, for some reason my current setup does not allow my guest to reach the internet. What settings do I need to enable both?
My Ubuntu Box has 3 interfaces. eth0 (Internal 192.168.1.0/24)eth1 (External ISP DHCP)eth2 (External ISP Static IP)I need the outgoing traffic to internet for 1 of the internal pc (192.168.1.10) to only go only go through eth2
today I tried to configure a network route to a host for testing my network interface. Code: route add 192.168.1.15 eth0 As I have to eth interfaces and both interface got their IP from DHCP (192.168.1.11 and 192.168.1.12) and are in the same subnet, I shut the other interface down:
Code: ifconfig eth1 down Then I tried to test the interface by doing a ping to 192.168.1.15. Problem: When I unplug the cable from eth0 (and eth1 is still plugged) the ping still works. Somehow my linux (it's debian) powers up again eth0 and pings over this port.
How can I stop my linux doing this. I just want to have the route added only on the one interface - not the other. Is it maybe some case of a default-gateway?
I've just put together a Centos 5.2 system using an old Future Domain SCSI card which would allow me to hook up an external DAT drive. On its BIOS screen it advertises itself as an AHA-2920 which should be handled by the aic7xxx module. However, the module doesn't even get loaded unless I force it in /etc/rc.modules and even then it doesn't pick up the card.
I have a problem reaching some hosts on the Internet, namely newegg.com and djangoproject.com. On the same machine and network connection using Windows 7 the host names resolve properly and I can connect to them. The host names are resolving in Ubuntu, but I cannot connect to them.
I'm using Ubuntu on my laptop but I'm having a small problem. The network is working fine except for the fact that I can't reach anything on my LAN (can't even ping the router), but everything on the outside works just fine. I can even visit my webserver if I type my public IP.
Where should I begin looking for faults?
Here, enjoy some data. I'm using my wlan0 interface, not sure whether eth0 works or not.
Quote:
$ route -n Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 192.168.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0 192.168.0.0 0.0.0.0 255.255.255.0 U 2 0 0 wlan0
I just had an ATT Uverse RG installed. However my Smoothwall router that previously worked fine with the ADSL SpeedStream is no longer accepting an address assignment DHCP ip address from this new gateway. (3800HGV-B)Any thoughts ideas or experience working with this hardware? ATT only supports Windows and Mac
I used my computer this morning before leaving for the office, but when I returned this evening, I am unable to reach the internet. Also the light on the mobo where the ethernet cable is plugged in is steady yellow.
My limited experience would tell me it is a hardware failure, but it seems so strange with nothing happening during the day. How might I best diagnose the problem from within Ubuntu (10.04)?
I'm running ubuntu 9.04 and I have set up 2 ip aliases using the /etc/network/interfaces file http://pastie.org/775037 -- when I ping the main address 10.0.2.16, all works fine, same with the first alias 10.0.2.22 -- but I can't reach the 2nd alias 10.0.2.23 I get the following from ping:
PING 10.0.2.23 (10.0.2.23): 56 data bytes Request timeout for icmp_seq 0 Request timeout for icmp_seq 1 Request timeout for icmp_seq 2 92 bytes from 10.5.0.1: Destination Host Unreachable Vr HL TOS Len ID Flg off TTL Pro cks Src Dst 4 5 00 5400 06eb 0 0000 3f 01 5e81 10.5.0.34 10.0.2.23
My machine's IP address is 10.5.0.34 I can't figure out why I can ping 10.0.2.22 but not 10.0.2.23 -- seems like there is probably some kind of routing thing that I'm missing, but I'm confused how it would have gotten set up for 10.0.2.22 but not 10.0.2.23 -- hopefully someone out there has an idea -- or can point me to references where I might be able to learn how to debug routing issues on a network?
I am working on a cluster for a molecular dynamics class and I have to edit my FORTRAN code (only the newest and best for me!). In order to get through to the cluster I have to ssh in. The network on which the cluster resides is behind a firewall, so I have to ssh through the firewall into the network first.
this is fine, I can login and move files and folders as needed, including sftp-ing into host 1, then into the cluster so I can transfer files from cluster to host and then host to me. This gets rather tiresome, so it would be nice to edit the files in place.
The problem is that when I access my code with emacs it launches the emacs client on Host 1, with no mouse support. I know the purists will howl about how I should be using keyboard shortcuts, but I am a chemist and not a programmer, so the mouse is very nice for me. Is there any way I can perhaps mount the cluster using sshfs so that when I open my code it launches a local instance of emacs? Sorry if this is the wrong forum, but I thought it was network related.
This has probably been beaten to death, but I can't find anything that fits my exact situation (maybe I'm using the wrong keywords, sorry).
Server:
eth0 - external NIC, DHCP IP from ISP eth1 - internal NIC, static 192.168.0.1 DHCP running on eth1 IPTABLES set up to masquerade on eth0
I have a computer connected up via server's eth1. It's IP is 192.168.0.201 (/etc/init.d/networking restart) gives me a DHCPOFFER and everything, so DHCP seems to be working fine.
Server:
can access internet I can ssh into 192.168.0.201 (even though it seems to take longer than usual)
192.168.0.201:
can ping server (well duh, I ssh'ed in from the server) cannot access internet for DNS on the internal NAT I'm using the same DNS servers as the router, so the server's
I have read many, learning linux,apache,samba,vsftp,ssh..etc from this forum but now i am realy stucked and confused. My samba server has always been reached from internal aswell external networks.
I have switched 5 months ago to Telfort network ( i am not sure... ) but as far as i know it was no poblem to connect the samba server with windows explorer everywhere.No i get the only the login screen when connecting from outside the network and when filling in the credentials it just come back with the login screen. I don't have any problems internal when connecting to these shares and supplying the credentials.
I use Fed 14. I have China Telecom internet. The wired dsl connection works fine, but the wireless won't work. It has WPA security. The password taken from beneath the router is n2nqrcqx. This password is accepted. Network Manager says I am connected to ChinaNet-TRtk, but in fact, I can't reach the internet via wireless. If I disconnect the cable, I can't get through. I have the settings on automatic dhcp. I have nothing in BSSID, I don't know what that is. I unchecked the box 'require ipv4 addressing for this connection to complete' Ditto that for ipv6.
I got a bunch of machines (~10) that I share with my co-workers. I have appropriate .ssh file(s) set up so I don't get prompt for password when I try to ssh.Currently I ssh into these hosts and then do a top to check the load before I start using the machine. Because I don't want to be on a busy host.Can someone show me how to write a script that find a least-busy host given a list of hosts to check? (hardcoded is fine)
I recently set up an Ubuntu server computer (10.04) with the hostname 'morbo', and with a static IP address. With all my other ubuntu systems i can ping and ssh using their host names, like:
[code]...
i can't reach it via 'morbo.local' nor can i reach my other ubuntu systems from morbo by their hostnames. I have seen a 'quick and dirty' solution which might help here : [URL]... , but i don't want to have to add every system to morbo's list and morbo to every systems list, and because it works without manual configuration on all my other systems, i don't see why it shouldn't be possible here. Currently everything connects to one d-link router - does this mean it is the DNS server?
I am not sure if this is a problem with my router or a problem with the fedora 12 server i am using.
- internal here means within my home network, external means from outside it.
I can access my server and webpage:
internally using http://192.168.0.192 externally using http://MYDNS___EXAMPLE.com
but I cannot access the server internally using http://MYDNS___EXAMPLE.com
This is a pain in the butt because I have all of my client software setup with an internal and external access point (ssh, proFTPd, http, MS Access database connected to MySql, etc.)
I have a simple home network with a windows and fedora clients. I'm running fedora 13, but I"m having problems connecting to the pc on certain ports from my windows pc. I can connect from windows to fedora using VNC, and even connect to my postgresql database. However, can not get connected to my Apache Tomcat or JBoss server. When I first installed the OS I went through and configured the firewall but have since disabled it (stopped service). However, I still can't get to the app/web servers.
i have sun Virtual box installed on my centos as my host os and centos as guest os.The ip on Sun virtual box virtual interface is10.0.2.15 and the ip on the physical machine is 192.168.1.11.when i try to ping the ip from my vps on centos to my physical machine it pings but it does't work when i try to ping my vps ip from my physical machine.Please recommend the route enteries i need to do in physical machine
I'm setting up my server under CentOS 5.5 (text mode) and I installed cherokee server but I couldn't reach it with the ip given by ifconfig. So I figured it might be an problem within cherokee. I also wanted to install webmin so I did that to see if I could reach that one. But also the webmin server is not reachable (I know the port number should be behind the ip ). So if I look up ifconfig I see the server has got an local ip (192.168.1.42) but I can't reach it from another computer in the same local network.
The internal network is behind nat done by the PC Router.The TP Link is recieving wireless signal from outdoors and it has switching and basic routing capabilities. I'm using the PC router for better routing options.PC Router (or R for short) is a triple-booting machine - Linux, FreeBSD and Windows. It has two lan cards - external (ext_if) - 100Mbps Realtek 8139 and internal (int_if) - 1Gbps integrated Realtek 8169.The problem is that all traffic from R to the network is slow - about 5-20K, while the traffic in the oppoiste direction is all right - about 10MB that is fine for 100Mbps cables, NICs and switches. The problem persist no matter the OS the pc R is running.I've tried some debugging on the situation as follows:
- put another PC at the place of R - everything is fine. That exclude the possibility of damaged cables, RJ-45s, switches and etc. - connected both of the NICs to the Internet while the internal network is being disconnected and they both work fine (no delays) - traffic shaping is not running - there is nothing in firewalls except NATing the internal network (and it is working fine). Actually these firewall rules have been operational for more than months and everything was fine untill a week or two ago. - changed the internal NIC with another - connected the internal network directly to the TP and all of the PCs are getting good network performance. Then connected the R machine to the TP as well and there was good performance between the internal network PCs and R. - R has good performance to the TP. In fact everything has good performance directly to the TP (when not connecting trough R). - the problem persist only between R and machines from the internal network.
I have to get soem statistic about interfaces from /proc/net/dev. but statistic on this file is reset when get reach more than 4G byte.I think linux has limitation on this case.
I'm trying to give some windows users a permanent connection to a samba share behind a firewall over the public Internet. I know I can give them access with something like winscp (which they have done) but really I'd like to do it with a VPN so it seems seamless to the user. However I have no idea how to set up the server to support this and am finding the documentation a bit confusing. The samba share is on a Debian box and the firwewall is a Linksys WRT54GL.
I have openvpn tunnel setup between two CentOS servers. One of the CentOS servers also acts as a DHCP server for some client computers.
Server A= OpenVPN server Server B= OpenVPN client (connects to Server A with OpenVPN)
The two CentOS servers can ping each other (172.16.0.0/24) via the tun0.
However, client computer connected to Server B (DHCP server) can't reach 172.16.0.1 (which is the OpenVPN server).
I think I am missing some routing in my "ip route show". Following is the full picture:
What command can I issue to get this fixed? something along ip route add?
There is no firewall service on both end. service iptables stop! I can't bridge eth1 and tun0 as DHCP server might mess up the other side. I can't do a push of "redirect-gateway def1" because then clients loose their IP as they send DHCP requests to Server A.
