Re: [LARTC] ip alias + dsl modem

[Alex Samad <alex@samad.com.au>]

[-- Attachment #1.1: Type: text/plain, Size: 3469 bytes --]

On Thu, Jan 25, 2007 at 12:14:56AM +0900, GodSharp wrote:
> Hi Guys,
> 
> Just wondering for some reason when I switched providers(DSL) IP aliasing
> stopped working. And, I am not sure what kind of modem this is, the previous
> one had some Ethernet ports at the back(it has a bult-in 4 port switch) the
> new doesn't have one, only a single Ethernet port and It is directly
> connected to my Linux box.
> 
> My provider gave me a /24 subnet and 9 useable IP's.
> 
> # ip a s eth2
> 6: eth2: <BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast qlen 1000
>     link/ether 00:08:a1:72:c1:f5 brd ff:ff:ff:ff:ff:ff
>     inet xxx.xxx.xxx.50/24 brd xxx.xxx.xxx.255 scope global eth2
>     inet xxx.xxx.xxx.51/24 brd xxx.xxx.xxx.255 scope global secondary eth2
>     inet xxx.xxx.xxx.52/24 brd xxx.xxx.xxx.255 scope global secondary eth2
>     inet xxx.xxx.xxx.53/24 brd xxx.xxx.xxx.255 scope global secondary eth2
>     inet xxx.xxx.xxx.54/24 brd xxx.xxx.xxx.255 scope global secondary eth2
>     inet xxx.xxx.xxx.55/24 brd xxx.xxx.xxx.255 scope global secondary eth2
>     inet xxx.xxx.xxx.56/24 brd xxx.xxx.xxx.255 scope global secondary eth2
>     inet xxx.xxx.xxx.57/24 brd xxx.xxx.xxx.255 scope global secondary eth2
>     inet xxx.xxx.xxx.58/24 brd xxx.xxx.xxx.255 scope global secondary eth2
> 
> -- settings --
> ip link set eth2 up
> ip addr flush dev eth2
> ip addr add xxx.xxx.xxx.50/24 brd xxx.xxx.xxx.255 dev eth2
> ip addr add xxx.xxx.xxx.51/24 brd xxx.xxx.xxx.255 dev eth2
> ip addr add xxx.xxx.xxx.52/24 brd xxx.xxx.xxx.255 dev eth2
> ip addr add xxx.xxx.xxx.53/24 brd xxx.xxx.xxx.255 dev eth2
> ip addr add xxx.xxx.xxx.54/24 brd xxx.xxx.xxx.255 dev eth2
> ip addr add xxx.xxx.xxx.55/24 brd xxx.xxx.xxx.255 dev eth2
> ip addr add xxx.xxx.xxx.56/24 brd xxx.xxx.xxx.255 dev eth2
> ip addr add xxx.xxx.xxx.57/24 brd xxx.xxx.xxx.255 dev eth2
> ip addr add xxx.xxx.xxx.58/24 brd xxx.xxx.xxx.255 dev eth2
> ip route add default via xxx.xxx.xxx.1
> --- end settings ---
> 
> /proc/sys/net/ipv4/ip_forward is 1
> /proc/sys/net/ipv4/ip_dynaddr is 1
> 
> works: ping google.com -I eth2
> works: ping google.com -I xxx.xxx.xxx.50
> not working: ping google.com -I xxx.xxx.xxx.58

have you tried ip route get it will tell you what the kernel is thinking on how
its going to route  the packet.

you might also need to setup some ip rule lines for each of the secondary
addresses.  but first try pinging the next hop with each of the addresses !

> 
> >From the outside I can ping xxx.xxx.xxx.50 but cannot ping any secondary
> IP's.
> 
> I tried tcpdump but didn't receive any replies from the secondary ip's I got
> replies from the primary IP though.
> 
> If I remove the secondary IP's and use it on another computer the secondary
> IP works. It looks like I can 
> only use 1 IP per computer(per mac). What seems to be the problem? Is it the
> modem? I am not sure about adsl's and their type of settings (bridge/router)
> and I would like to contact my provider. But I am having troubles on asking
> them regarding the problem. If there's a technical explanation regarding
> this or some trick it would help me clarify them or me.
> 
> There are no filters involved(iptables). On my previous provider aliasing
> works both are dsl's.
> 
> _______________________________________________
> LARTC mailing list
> LARTC@mailman.ds9a.nl
> http://mailman.ds9a.nl/cgi-bin/mailman/listinfo/lartc
> 

[-- Attachment #1.2: Digital signature --]
[-- Type: application/pgp-signature, Size: 189 bytes --]

[-- Attachment #2: Type: text/plain, Size: 143 bytes --]

_______________________________________________
LARTC mailing list
LARTC@mailman.ds9a.nl
http://mailman.ds9a.nl/cgi-bin/mailman/listinfo/lartc