I had one server that was in production suddenly become no longer responsive w.r.t network. No settings have been changed in a while, so I don't really understand why it would go wrong. It looks like a routing issue, but don't know how to progress from here.
I tried loading rescue cd and seeing if there's any hardware issue, but temporary OS had no issue connecting via network.
Here are some info: (to note, eth0 is what I use for lan, eth1 is what I use for internet)
# route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
149.255.34.168 * 255.255.255.248 U 0 0 0 eth1
192.168.1.0 * 255.255.255.0 U 0 0 0 eth0
link-local * 255.255.0.0 U 1002 0 0 eth0
link-local * 255.255.0.0 U 1003 0 0 eth1
default 149.255.34.169 0.0.0.0 UG 0 0 0 eth1
Pinging any other devices in vlan/self works fine.
# ping 192.168.1.1
PING 192.168.1.1 (192.168.1.1) 56(84) bytes of data.
64 bytes from 192.168.1.1: icmp_seq=1 ttl=64 time=0.129 ms
64 bytes from 192.168.1.1: icmp_seq=2 ttl=64 time=0.193 ms
64 bytes from 192.168.1.1: icmp_seq=3 ttl=64 time=0.137 ms
...
Other devices in the vlan can connect to this machine as well.
But any via internet is not
# ping 8.8.8.8
PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.
64 bytes from 8.8.8.8: icmp_seq=1 Destination Host Unreachable
64 bytes from 8.8.8.8: icmp_seq=2 Destination Host Unreachable
64 bytes from 8.8.8.8: icmp_seq=3 Destination Host Unreachable
...
and ifconfig.
# ifconfig
eth0 Link encap:Ethernet HWaddr 00:25:90:53:9D:D3
inet addr:192.168.1.4 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: fe80::225:90ff:fe50:1abf/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:21 errors:0 dropped:0 overruns:0 frame:0
TX packets:38 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:1830 (1.7 KiB) TX bytes:2868 (2.8 KiB)
Interrupt:20 Memory:fba00000-fba20000
eth1 Link encap:Ethernet HWaddr 00:25:90:53:9D:D2
inet addr:149.255.34.173 Bcast:149.255.34.175 Mask:255.255.255.248
inet6 addr: fe80::225:90ff:fe50:1abe/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0 <--- nothing ever recieved
TX packets:730 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:31092 (30.3 KiB)
Interrupt:16 Memory:fb900000-fb920000
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:497 errors:0 dropped:0 overruns:0 frame:0
TX packets:497 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:54618 (53.3 KiB) TX bytes:54618 (53.3 KiB)
and it's settings (which is same as another server that's running fine, with exception of assigned ip)
#cat /etc/sysconfig/network-scripts/ifcfg-eth1
DEVICE="eth1"
BOOTPROTO=static
BROADCAST=149.255.34.175
DNS1=8.8.8.8
GATEWAY=149.255.34.169
HWADDR=00:25:90:50:9D:D2
IPADDR=149.255.34.173
IPV6INIT=yes
IPV6_AUTOCONF=yes
NETMASK=255.255.255.248
NM_CONTROLLED=yes
ONBOOT=yes
TYPE=Ethernet
UUID=*************
Edit for more info
# cat /etc/sysconfig/network
NETWORKING=yes
HOSTNAME=173.34.255.149
GATEWAY=149.255.34.169
I cannot ping my gateway. It's another Destination Host Unreachable
Unfortunately, traceroute (or similar) is not installed on the server right now and cannot install due to absence of network.
I have checked with iptables as off.
Just to bring closure to this.
Though other sys admins have looked at the server, no one was able to find any software related issue. I suspect it was an ethernet adapter failure and so does the host. A brand new server replaced it to come to a solution.
Your HWADDR in /etc/sysconfig/network-scripts/ifcfg-eth1 is wrong.
and your ifconfig eth1 output is
Correct the HWADDR and let's see if this fixed your problem.