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dianam

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IP Aliasing and kernel 2.2.16 vs 2.2.19

I'm building a Slackware server for Web hosting that will need to use IP based hosting for SSL.  The kernel I currently have is 2.2.16 and I have been told that 2.2.16 does not support IP Aliasing so I cannot assign multiple IP addresses to the same NIC.  I have also been told that I should upgrade to 2.2.19.

Is there a workaround on 2.2.16 that will allow me to use multiple addresses on the same NIC or do I have to go to the 2.2.19 kernel?

For that matter, does the 2.2.19 kernel support IP aliasing?

TIA,
Diana
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vreddypatil

I think 2.2.16 supports ip aliasing, You have to conifgure
your kernel for ip aliasing
Or just try this to know wheteher you kernel supports ip aliasisng ot not.
Linux# ifconfig eth:0 192.168.1.1 netmask 255.255.255.0 up
if it gives error thenn you have to enable support for aliasing in kernel configuration.

Hope this helps

--Vijayapal
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ASKER

Thanks for your comment but I have already tried that.  I found out from the Slackware forum that 2.2.16 does not include ip_alias.o so there is no aliasing support to enable in that particular kernel.

Again, thank you for responding.
Diana
Diana:

Kernel 2.2.12 on a redhat distribution definitely includes ip aliasing support. It doesn't include ip_alias.o - aliasing is compiled into the kernel, rather than made available as a module. The ifconfig command quoted above isn't quite correct - it needs to be

ifconfig eth0:0 <ipaddress> netmask <netmask> up

and it needs to be executed as root. Then execute ifconfig to examine the results.

If it doesn't work, then you have a kernel which has been compiled without aliasing support, either built-in or as a module. In this case, I would recommend acquiring the kernel sources and recompiling. As you're building a web server, this is not a bad idea anyway, because you'll be able to fine-tune the kernel for optimal performance as well.


Vijay
An old problem with default slackware kernel is that is not compiled with IP aliasing (and IP aliasing is not available as a module). You will have to simply recompile your kernel. If kernel recompilation scares you, do not enable or disable anything except support for IP aliasing (it is in networking options group). To recompile your kernel, install teh kernel source (k1/linux.tgz) and do that:

su
cd /usr/src/linux
make menuconfig
....(enable IP aliasing in config)....
make dep bzlilo modules modules_install
reboot

----
Radu-Adrian Feurdean
Brainbench Linux MVP
 www.brainbench.com

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SpideyMod

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