Due to a lack of IP address I am changing our subnet mask from 192.168.0.0/24 to 192.168.0.0/22. We use IP address 192.168.0.4 as our squid server and I am trying to change the subnet mask so that workstations with addresses 192.168.1.x - 192.168.3.x will be able to use squid as the proxy server.

I am new to Linux but so far I have edited the squid.conf and changed 2 lines to read

acl myIP src 192.168.0.4/255.255.252.0
acl myIP src 192.168.0.0/255.255.252.0

I now need to change the subnet mask for the Linux server. I have run the command 'ifconfig -a' and received the following

eth0 - inet addr:192.168.0.4 Bcast:192.168.0.255 Mask:255.255.255.0

I then ran the command 'ifconfig eth0 netmask 255.255.252.0'

When I check the config again the new mask is displayed but nothing can use the squid server. Further more if I run 'ifdown eth0' and then 'ifup eth0' the mask reverts back to 255.255.255.0 (but at least the workstations's can use squid again).

1. Do I need to save it (similar to wr mem with a cisco box)
2. Do I need to change the BCast (assuming 192.168.3.255 as this will be the end of the /22 range).
3. Is there something else I need to configure?

I am using Red Hat (unsure which build - is there an easy way to find out)

Thanks

JHM

did you changed the netmask on all the computers, or in the DHCP server if any?

Repo,

Thanks for the quick response.

I haven't changed the DHCP range yet until I get the proxy working. I have changed the netmask on servers and the firewall but they are still all on 192.168.0.x anyway so chaging the netmask on the proxy to /22 should have no effect.

Having said that I just run 'shutdown -r now' and a test machine with ip address 192.168.1.x can now access the internet via the proxy so I am guessing that changing this config:-

acl myIP src 192.168.0.4/255.255.252.0
acl myIP src 192.168.0.0/255.255.252.0

followed by the shutdown appears to have worked.

I may try to chage the netmask also of eth0 but if this works I may well leave it. Do you think I need to shutdown and restart after making the changes? Also, are the changes permanent or do they need to be written?

JHM

Restart networking, should be OK