[Mageia-discuss] Temporarily changing IP address

Tue May 22 19:51:08 CEST 2012

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+> Hash: SHA1
+>
+> On 22/05/12 16:59, AL13N wrote:
+>>> On 22/05/12 15:08, AL13N wrote:
+>>>>>>> No :-(  No difference, even though I restarted the
+>>>>>>> network service,
+>>>>>
+>>>>> Lets start from scratch.
+>>>>>
+>>>>> But first, can you tell me the ip address of the NAS and
+>>>>> your laptop's IP address for eth0.
+>>>>>
+>>>>> After making note of these, put the laptop back to it's
+>>>>> original config. (i.e. remove the manually created interface)
+>>>>> and set wlan0 not to come up on reboot.  Then restart so you
+>>>>> only have an ip address on eth0.
+>>>>>
+>>>>> Then send me the info.
+>>>>>
+>>>>> Doug
+>>>>
+>>>> in fact, if we want it to be even simpler, you could add the
+>>>> ip address without a alias interface wit iproute2
+>>>>
+>>>> []# ip addr show eth0
+>>>
+>>> # ip addr show eth0 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP>
+>>> mtu 1500 qdisc pfifo_fast state UP qlen 1000 link/ether
+>>> 1c:75:08:28:bd:e4 brd ff:ff:ff:ff:ff:ff inet 169.254.100.1/24 brd
+>>> 169.254.100.255 scope global eth0 inet6
+>>> fe80::1e75:8ff:fe28:bde4/64 scope link valid_lft forever
+>>> preferred_lft forever
+>>>
+>>>> []# ip addr add www.xxx.yyy.zzz/netmask dev eth0
+>>>
+>>> # ip addr add www.192.168.0.20/255.255.255.0 dev eth0 Error: an
+>>> inet prefix is expected rather than
+>>> "www.192.168.0.20/255.255.255.0".
+>>>
+>>> Not sure what it is expecting.
+>>
+>> hum, i meant the socalled CIDR notation: 4 parts of ip address
+>> followed by a subnet mask,
+>>
+>> in your case, i'd do:
+>>
+>> []# ip addr add 192.168.0.20/24 dev eth0
+>>
+> Meanwhile, I played with alternatives, knowing that it must be
+> something close to what I'd already tried.  So,
+>
+> # ip addr add 192.168.0.20/255.255.255.0 dev eth0
+> # ip addr show eth0
+> 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast
+> state UP qlen 1000
+>     link/ether 1c:75:08:28:bd:e4 brd ff:ff:ff:ff:ff:ff
+>     inet 169.254.100.1/24 brd 169.254.100.255 scope global eth0
+>     inet 192.168.0.20/24 scope global eth0
+>     inet6 fe80::1e75:8ff:fe28:bde4/64 scope link
+>        valid_lft forever preferred_lft forever
+>
+> So now it appears to have two addresses, preferring the wrong one.
+
+
+by preferring, you mean the top one?
+
+
+>> then if you do
+>>
+>> []# ip addr show eth0
+>>
+>> again, you'd see it was there, as well as the extra route for that
+>> range:
+>>
+>> []# ip route
+>>
+> # ip route
+> default via 192.168.0.1 dev eth1  proto static
+> default via 169.254.100.100 dev eth0  metric 10
+> default via 192.168.0.1 dev eth1  metric 10
+> 169.254.100.0/24 dev eth0  proto kernel  scope link  src 169.254.100.1
+>  metric 10
+> 192.168.0.0/24 dev eth1  proto kernel  scope link  src 192.168.0.101
+> 192.168.0.0/24 dev eth0  proto kernel  scope link  src 192.168.0.20
+
+
+whoa, 3 default routes? over different interfaces...
+
+you have 192.168.0.0/24 network, both reachable over eth1 and eth0, i hope
+that is what you want...
+
+
+>>
+> ifconfig
+> eth0      Link encap:Ethernet  HWaddr 1C:75:08:28:BD:E4
+>           inet addr:169.254.100.1  Bcast:169.254.100.255
+> Mask:255.255.255.0
+>
+>>>
+>>> Shorewall and iptables are currently stopped.
+>>
+>> Be careful of this, in your case, it might not matter, but
+>> shorewall stop has policy DROP, (i think), allthough iptables
+>> should have policy ACCEPT.
+>>
+>> so, you'd have to stop shorewall first, then stop iptables.
+>
+> That's the order I did it.
+>>
+>> personally, i'd rather not stop the firewall, due to security
+>> reasons though. but since with this solution, you don't have any
+>> extra interface, even just restarting it would be fine.
+>>
+> Once I have a connection I'll restart them.
+>
+>> if you want to debug even further:
+>>
+>> []# tcpdump -n -i eth0 host <nas_ip>
+>>
+> Where does that write to?  A log file?
+>
+>> and try to connect and then you can see what sourceip and destip
+>> are set and if a reply is coming back.
+>>
+> At the end of this, though, I can ping both the NAS on 192.168.0.200
+> and other LAN connections.
+>
+> Last question, then, is whether this is a permanent change?
+
+ip command is never permanent, you have to change the config files if you
+want permanent changes (ie: after reboot).
+