Gentoo Archives: gentoo-user

From: Grant <emailgrant@×××××.com>
To: gentoo-user@l.g.o
Subject: Re: [gentoo-user] IP aliasing problem
Date: Fri, 08 Oct 2010 17:13:49
Message-Id: AANLkTimpt2tG479XK6301_DgaynQUDXwyYrPw2meNHGk@mail.gmail.com
In Reply to: Re: [gentoo-user] IP aliasing problem by Stroller
1 >>> ServerName differently for  each VirtualHost.  Strangely though, I
2 >>> still don't get stats for RX/TX  from ifconfig:
3 >>>
4 >>> eth0      Link encap:Ethernet  HWaddr  [removed]
5 >>>          inet addr:1.2.3.1   Bcast:[removed]  Mask:255.255.255.248
6 >>>           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
7 >>>           RX packets:923677 errors:0 dropped:0 overruns:0  frame:0
8 >>>          TX packets:1444212 errors:0  dropped:0 overruns:0 carrier:0
9 >>>           collisions:0 txqueuelen:1000
10 >>>          RX  bytes:124904402 (119.1 MiB)  TX bytes:1880087116 (1.7 GiB)
11 >>>           Interrupt:40
12 >>>
13 >>> eth0:1    Link  encap:Ethernet  HWaddr [removed]
14 >>>          inet  addr:1.2.3.2  Bcast:[removed]  Mask:255.255.255.248
15 >>>           UP BROADCAST RUNNING MULTICAST  MTU:1500   Metric:1
16 >>>          Interrupt:40
17 >>
18 >> Remember eth0:1 is an alias for eth0.
19 >>
20 >> Your above info is slightly wrong in that eth0 should be listed as eth0:0; where
21 >> instead ifconfig is showing eth0 generic information and eth0:0 information
22 >> combined.
23 >> That's probably the source of your confusion.
24 >
25 > On a system running 2.4.25 here I have:
26 >
27 > $ ifconfig
28 > eth0      Link encap:Ethernet  HWaddr 00:02:A5:1B:01:59
29 >          inet addr:213.x.y.91  Bcast:213.x.y.95  Mask:255.255.255.248
30 >          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
31 >          RX packets:211366804 errors:0 dropped:0 overruns:0 frame:0
32 >          TX packets:306200382 errors:0 dropped:0 overruns:0 carrier:0
33 >          collisions:0 txqueuelen:1000
34 >          RX bytes:1542358934 (1470.9 Mb)  TX bytes:1547826181 (1476.1 Mb)
35 >          Interrupt:20 Base address:0xd000
36 >
37 > eth0:1    Link encap:Ethernet  HWaddr 00:02:A5:1B:01:59
38 >          inet addr:192.168.1.43  Bcast:192.168.255.255  Mask:255.255.255.0
39 >          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
40 >          RX packets:211366804 errors:0 dropped:0 overruns:0 frame:0
41 >          TX packets:306200384 errors:0 dropped:0 overruns:0 carrier:0
42 >          collisions:0 txqueuelen:1000
43 >          RX bytes:1542358934 (1470.9 Mb)  TX bytes:1547826521 (1476.1 Mb)
44 >          Interrupt:20 Base address:0xd000
45 >
46 > lo        Link encap:Local Loopback
47 > ...
48 >
49 >
50 > The same TX & RX are shown for both interfaces.
51 >
52 > I don't know whether the tools have changed much since those I'm using on this box, but the difference *might* be that Grant's IPs are on the same subnet. I *think* it's possible for the route (as in: `man route`) to configure packets that come in on 1.2.3.2 to be replied to via 1.2.3.1.
53 >
54 > You might set up a spare test box to see how current ifconfig displays packets, comparing aliased addresses on the same and separate subnets.
55 >
56 > Stroller.
57
58 OK, thanks guys.
59
60 - Grant

Replies

Subject Author
Re: [gentoo-user] IP aliasing problem Adam Carter <adamcarter3@×××××.com>