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I am confused about the meaning of 192.168.x.x (private network). In DSL bridge mode, my computer has been assigned an IP as part of ISP's private network such as 36.82.x.x. It also can connect to the outside world through an public IP.
In LAN, 192.168.1.1 will be my router, 192.168.1.x is another computers connected to the router (as assigned by DHCP server).
I would like to know what is the rule if I connect to DSL network? I can still see 192.168.1.1 but this is not my own router. Scanning this range shows that there are also several live IPs such as 192.168.1.161, 192.168.1.162, etc. They are not part of my private network.
Edit:
I'm doing nmap
scan to 192.168.1.0/24
while in bridging mode. I can see several IPs are alive which are not mine. I don't know much about how bridging to ISP works, but I assume that after bridging, 192.168.x.x
are not my private network.
Add Output:
# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> ...
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
2: eth0: <NO-CARRIER,BROADCAST,MULTICAST,UP> ...
...
3: wlan0: <NO-CARRIER,BROADCAST,MULTICAST,UP> ...
...
5: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> ...
link/ether f8:d1:11:bc:9f:06 brd ff:ff:ff:ff:ff:ff
inet6 fe80::fad1:11ff:febc:9f06/64 scope link
valid_lft forever preferred_lft forever
6: ppp0: <POINTTOPOINT,MULTICAST,NOARP,UP,LOWER_UP> ...
link/ppp
inet 125.164.x.x peer 125.164.x.x/32 brd 125.164.x.x scope global ppp0
# traceroute 192.168.1.1
traceroute to 192.168.1.1 (192.168.1.1), 30 hops max, 60 byte packets
1 125.164.xx.1
2 125.164.xx.1
3 118.98.xx.xx
4 61.94.xx.xx
5 61.94.xx.xx
6 118.98.xx.xx
7 118.98.xx.xx
8 192.168.1.1
It requires 8 hops to reach 192.168.1.1.
You first two paragraphs make sense but then in your last paragraph it suddenly becomes unclear what you're talking about. Are you still talking about bridging to your ISP? Or are you talking about connecting some other way? – David Schwartz – 2013-12-26T08:04:43.257
"my computer has been assigned an IP as part of ISP's private network such as 36.82.x.x." -- That's because you are (mis)using
bridge mode
on your modem/router, which exposes your PC to the Internet. You need a router in between your ISP and all of your PCs to provide a firewall and NAT for protection. Then this 36.82.x.x IP address would be assigned to the WAN side of the router. 192.168.1.1 is often assigned to the LAN side of the router. The DHCP server in the router should then hand out IP addresses in its assigned range, apparently 192.168.1.xxx. – sawdust – 2013-12-26T09:35:40.317@DavidSchwartz: yes, I'm still talking about bridging to ISP. I use
nmap
to scan192.168.1.1-255
and I found several IPs which are not mine. – David Bower – 2013-12-26T15:55:20.643@sawdust: yes, I know that 192.168.1.1 is often assigned to the LAN side. IP in range 192.168.x.x usually are anything belong to me. But when I'm doing bridging to ISP, I can still see 192.168.1.1 IP which is not mine. I would like know who owned or assigned them? – David Bower – 2013-12-26T15:58:04.467