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I have a CentOS 6 machine that Im using for Nagios. Its a Dell PowerEdge server that's off warranty and has 2 onboard NICs and 2 more in a card. It has been running Nagios for several months and working fine. The 2 onboard are running while the 2nd pair are inactive.

Recently I came into possession of a water/temp/light sensor from eesensors.com that plugs into a NIC and is compatible with Nagios. I compiled the Nagios plugin, hooked it up to one of the 2nd NICs, configured 'ifcfg-p3p1' per what seemed appropriate (*) and ran 'ifup-p3p1'.

At this point, 'ifconfig' shows the new port up and packets going through. What also happens is that the original ports appear to stop working. Apache is non-responsive and Nagios is reports errors from every test. I am still able to communicate with the server via SSH. To fix this issue I have to restart the network, which starts eth1 but not p3p1.

So -

  • what did I do wrong in bringing up the additional port?
  • why would my HTTPD, etc services stop responding even though SSH works? I would figure if the NIC is down then that takes SSH with it.
ifcfg-p3p1:    
    DEVICE=p3p1   
    HWADDR=00:0E:0C:xx:xx:xx    
    ONBOOT=no    
    BOOTPROTO=static    
    IPADDR=192.168.0.1   
    NETMASK=255.255.255.0   
    GATEWAY=192.168.0.2    

ifcfg-eth1:    
    DEVICE="eth1"   
    HWADDR="00:14:22:xx:xx:xx"   
    NM_CONTROLLED="yes"  
    ONBOOT="yes"  
    IPADDR=10.127.24.21  
    GATEWAY=10.127.24.1  
    NETMASK=10.127.254.0  
    NETWORK=10.127.24.0  
    TYPE=ETHERNET  


[root@orange network-scripts]# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN
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

2: eth0: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast state DOWN qlen 1000
link/ether 00:14:22:13:b7:f3 brd ff:ff:ff:ff:ff:ff

3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:14:22:13:b7:f4 brd ff:ff:ff:ff:ff:ff
inet 10.127.24.21/23 brd 10.127.25.255 scope global eth1
inet6 fe80::214:22ff:fe13:b7f4/64 scope link
   valid_lft forever preferred_lft forever

4: p3p1: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast state DOWN qlen 1000
link/ether 00:0e:0c:71:82:ae brd ff:ff:ff:ff:ff:ff

5: p3p2: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast state DOWN qlen 1000
link/ether 00:0e:0c:71:82:af brd ff:ff:ff:ff:ff:ff

[root@orange network-scripts]# ip route
10.127.24.0/23 dev eth1  proto kernel  scope link  src 10.127.24.21
169.254.0.0/16 dev eth1  scope link  metric 1003
default via 10.127.24.1 dev eth1

[root@orange network-scripts]# ifup p3p1

[root@orange network-scripts]# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN
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

2: eth0: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast state DOWN qlen 1000
link/ether 00:14:22:13:b7:f3 brd ff:ff:ff:ff:ff:ff

3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:14:22:13:b7:f4 brd ff:ff:ff:ff:ff:ff
inet 10.127.24.21/23 brd 10.127.25.255 scope global eth1
inet6 fe80::214:22ff:fe13:b7f4/64 scope link
   valid_lft forever preferred_lft forever

4: p3p1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0e:0c:71:82:ae brd ff:ff:ff:ff:ff:ff
inet 192.168.0.1/24 brd 192.168.0.255 scope global p3p1
inet6 fe80::20e:cff:fe71:82ae/64 scope link
   valid_lft forever preferred_lft forever

5: p3p2: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast state DOWN qlen 1000
link/ether 00:0e:0c:71:82:af brd ff:ff:ff:ff:ff:ff

[root@orange network-scripts]# ip route
192.168.0.0/24 dev p3p1  proto kernel  scope link  src 192.168.0.1
10.127.24.0/23 dev eth1  proto kernel  scope link  src 10.127.24.21
169.254.0.0/16 dev eth1  scope link  metric 1003
169.254.0.0/16 dev p3p1  scope link  metric 1004
default via 192.168.0.2 dev p3p1
share|improve this question
    
Could you post the content of the p3p1 config file and possibly the eth0 config file. –  Flash Apr 24 '12 at 15:14
    
edited to include working (eth1) and obstinate (p3p1) cfg files –  ethrbunny Apr 24 '12 at 15:22
    
Post the output of ip addr and ip route before and after ifuping p3p1. Does Apache work from localhost? Anything in dmesg? –  MikeyB Apr 24 '12 at 15:23

1 Answer 1

up vote 3 down vote accepted

Remove this line:

GATEWAY=192.168.0.2    

There is no gateway there!

Any service that requires use of a gateway will break if you specify an IP address that's not actually a gateway as a gateway.

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