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Old 01-21-2009, 05:48 AM   #1
JHMorris
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Squid stops working after subnet mask change


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
 
Old 01-21-2009, 05:56 AM   #2
repo
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did you changed the netmask on all the computers, or in the DHCP server if any?
 
Old 01-21-2009, 06:47 AM   #3
JHMorris
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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

Last edited by JHMorris; 01-21-2009 at 06:49 AM.
 
Old 01-21-2009, 07:05 AM   #4
repo
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Quote:
Do you think I need to shutdown and restart after making the changes?
Restart networking, should be OK
 
  


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