[Mageia-discuss] Temporarily changing IP address

Tue May 22 18:12:07 CEST 2012

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+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.
+
+> 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
+> 
+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?
+
+Anne
+
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