1

My Uni provided me two hostnames and static IPs for two interfaces on my Fedora Server 23. My idea is to use one hostname for production and another for dev branches. It should work as: bio-db.uni.edu on interface eno2 with xxx.xxx.86.24 IP and bio-db-dev.uni.edu on eno1 with with xxx.xxx.86.64 IP. Server is CherryPy (two instances bound to given static IPs)

I ran one interface eno2 for months now, but when I opened up second interface with ifconfig eno1 up, I received message from IT department that there is a conflict:

Network access for xx:xx:xx:xx:xx:71 (bio-db.uni.edu) has been disabled at 04/26/16 15:34:54:

  Reason: Host using incorrect IP address
    MAC xx:xx:xx:xx:xx:71 IP xxx.xxx.xxx.64 found in rtr30 cache
  Switch: switch.uni.edu
  Port:   52051

It appears a bit random: sometime eno1 get disabled, sometimes eno2, but they always get these two IPs mixed up.

How I can debug this? I am in touch with IT people, but also want to know if that is something my serve is doing wrong. Which logs might help me?

When IPs are allocated by DHCP, hosts become accessible as supposed, my ifconfig looks like that right after I bring interfaces up:

# uname -a
Linux bio-db.uni.edu 4.3.5-300.fc23.x86_64 #1 SMP Mon Feb 1 03:18:41 UTC
2016 x86_64 x86_64 x86_64 GNU/Linux

# ifconfig eno1 <-- is 'bio-db-dev.uni.edu'
eno1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet xxx.xxx.86.64 netmask 255.255.254.0 broadcast xxx.xxx.87.255
inet6 __IPV6__ prefixlen 64 scopeid 0x20<link>
ether xx:xx:xx:xx:xx:70 txqueuelen 1000 (Ethernet)
RX packets 63597 bytes 10057016 (9.5 MiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 2504 bytes 1899384 (1.8 MiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
device interrupt 16

# ifconfig eno2 <-- is 'bio-db.uni.edu'
eno2: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet xxx.xxx.86.24 netmask 255.255.254.0 broadcast xxx.xxx.87.255
inet6 __IPV6__ prefixlen 64 scopeid 0x20<link>
ether xx:xx:xx:xx:xx:71 txqueuelen 1000 (Ethernet)
RX packets 11575 bytes 1834587 (1.7 MiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 417 bytes 68578 (66.9 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
device interrupt 17

Added ip address and ip route listing

# ip address
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: eno1: <BROADCAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether 40:f2:e9:bd:97:70 brd ff:ff:ff:ff:ff:ff
    inet xxx.xxx.86.64/23 brd xxx.xxx.87.255 scope global eno1
       valid_lft forever preferred_lft forever
    inet6 fe80::42f2:e9ff:febd:9770/64 scope link 
       valid_lft forever preferred_lft forever
3: eno2: <BROADCAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether 40:f2:e9:bd:97:71 brd ff:ff:ff:ff:ff:ff
    inet xxx.xxx.86.24/23 brd xxx.xxx.87.255 scope global eno2
       valid_lft forever preferred_lft forever
    inet6 fe80::42f2:e9ff:febd:9771/64 scope link 
       valid_lft forever preferred_lft forever
4: eno3: <BROADCAST,MULTICAST> mtu 1500 qdisc mq state DOWN group default qlen 1000
    link/ether 40:f2:e9:bd:97:72 brd ff:ff:ff:ff:ff:ff
5: eno4: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether 40:f2:e9:bd:97:73 brd ff:ff:ff:ff:ff:ff
    inet 192.168.0.40/24 brd 192.168.0.255 scope global eno4
       valid_lft forever preferred_lft forever
    inet6 fe80::42f2:e9ff:febd:9773/64 scope link 
       valid_lft forever preferred_lft forever
6: ens1f0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN group default qlen 1000
    link/ether 90:e2:ba:b6:f7:34 brd ff:ff:ff:ff:ff:ff
7: ens1f1: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN group default qlen 1000
    link/ether 90:e2:ba:b6:f7:35 brd ff:ff:ff:ff:ff:ff
8: enp0s20u13u5: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UNKNOWN group default qlen 1000
    link/ether 42:f2:e9:bd:97:77 brd ff:ff:ff:ff:ff:ff
    inet 169.254.95.120/24 brd 169.254.95.255 scope link dynamic enp0s20u13u5
       valid_lft 541sec preferred_lft 541sec
    inet6 fe80::40f2:e9ff:febd:9777/64 scope link 
       valid_lft forever preferred_lft forever
9: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default qlen 1000
    link/ether 52:54:00:d8:5d:36 brd ff:ff:ff:ff:ff:ff
    inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0
       valid_lft forever preferred_lft forever
10: virbr0-nic: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue master virbr0 state DOWN group default qlen 500
    link/ether 52:54:00:d8:5d:36 brd ff:ff:ff:ff:ff:ff

# ip route
default via xxx.xxx.86.1 dev eno2  proto static  metric 100 
default via xxx.xxx.86.1 dev eno1  proto static  metric 101 
xxx.xxx.86.0/23 dev eno2  proto kernel  scope link  src xxx.xxx.86.24  metric 100 
xxx.xxx.86.0/23 dev eno1  proto kernel  scope link  src xxx.xxx.86.64  metric 101 
xxx.xxx.253.244 via xxx.xxx.86.1 dev eno2  proto dhcp  metric 100 
169.254.95.0/24 dev enp0s20u13u5  proto kernel  scope link  src 169.254.95.120  metric 100 
192.168.0.0/24 dev eno4  proto kernel  scope link  src 192.168.0.40  metric 100 
192.168.122.0/24 dev virbr0  proto kernel  scope link  src 192.168.122.1 
6
  • Please post the output of ip address and ip route ... and update your system. Apr 27, 2016 at 19:54
  • @MichaelHampton done, upgrade in progress Apr 27, 2016 at 20:11
  • Hmm. Both of these NICs appear to be on the same subnet. That's the basic problem. Why bother with two NICs, then? You could just use one. Apr 27, 2016 at 20:24
  • @MichaelHampton It is the same NIC with 4x1GbE. What I want to have is two host names on same machine. One links to production server, another on dev. My Uni gives away host name and static IP per request, one pair per MAC. Is there way to achieve this? Apr 27, 2016 at 20:54
  • Get the university to allow both IP addresses on the same MAC address, that's the easiest solution. At least for you. They might not want to do it though. Apr 27, 2016 at 20:58

0

You must log in to answer this question.

Browse other questions tagged .