Very Computer

> Hello
> I have a small home LAN as follows:

> Firewall (Smoothwall - ext ISDN; int eth0)
> |
> Crossover cable
> |
> Proxy server (Suse 10 with Squid - ext eth0; int eth1)
> |
> Switch
> |
> Clients (Windows XP)
> |
> |
> On the firewall my external interface is dynamic (ISDN) Internal is
> 192.168.0.1
> Gateway is 192.168.0.1

> On Squid external is DHCP from Smoothwall (eg. 192.168.0.100) Internal is
> 192.168.40.1
> Gateway is 192.168.0.1

> The clients are set by DHCP from Squid

> I am not a Linux expert by any means, but I have successfully set up the
> Windows XP clients to go through Squid and Dansguardian on the proxy.
> However, as Squid is only a HTTP proxy I can't get access to my ISP'sPOP
> and news servers, at least from the clients.  I can from Squid. I
> understand that to do this I need to enable NAT and packet forwarding on
> Squid.

> I *think* I have done this properly, but I am not sure.  When I start
> Outlook on Windows and run Ethereal on Squid to capture the packets I see
> that my Windows clients can't find 192.168.0.1.  The ARP broadcast just
> runs and runs with no answer, and they can't find the gateway.  I have
> tried turning off the firewall on Squid, with no joy.  I have tried to set
> up a caching DNS server on Squid, but I don't have enough expertise to
> know that what I am doing is right.

> Is there anyone who can help me resolve this please?  I have looked and
> looked on the internet but it's difficult to trawl through all the
> questions and find the right answer.

> Some information that might be helpful: Ethereal capturing packets on
> Squid's internal interface while running Outlook Send/receive on Linux
> client: Windows PC sends DNS query mail.iol.ie Squid replies ICMP
> Destination unreachable (port unreachable) Windows then sends NetBIOS name
> query mail.iol.ie to 192.168.40.255 This request just loops

> Hello
> I have a small home LAN as follows:
> |
> Firewall (Smoothwall - ext ISDN; int eth0)
> |
> Crossover cable
> |
> Proxy server (Suse 10 with Squid - ext eth0; int eth1)
> |
> Switch
> |
> Clients (Windows XP)
> |
> On the firewall my external interface is dynamic (ISDN)
> Internal is 192.168.0.1
> Gateway is 192.168.0.1
> On Squid external is DHCP from Smoothwall (eg. 192.168.0.100)
> Internal is 192.168.40.1
> Gateway is 192.168.0.1
> The clients are set by DHCP from Squid
> I am not a Linux expert by any means, but I have successfully set up the
> Windows XP clients to go through Squid and Dansguardian on the proxy.
> However, as Squid is only a HTTP proxy I can't get access to my ISP'sPOP
> and news servers, at least from the clients.  I can from Squid. I
> understand that to do this I need to enable NAT and packet forwarding on
> Squid.
> I *think* I have done this properly, but I am not sure.  When I start
> Outlook on Windows and run Ethereal on Squid to capture the packets I see
> that my Windows clients can't find 192.168.0.1.  The ARP broadcast just
> runs and runs with no answer, and they can't find the gateway.  I have
> tried turning off the firewall on Squid, with no joy.  I have tried to set
> up a caching DNS server on Squid, but I don't have enough expertise to
> know that what I am doing is right.

>> Some information that might be helpful: Ethereal capturing packets on
>> Squid's internal interface while running Outlook Send/receive on Linux
>> client: Windows PC sends DNS query mail.iol.ie Squid replies ICMP
>> Destination unreachable (port unreachable)

> For what it's worth, that ICMP message essentially means nothing is
> listening on the port.  No DNS server running on the port means no IP
> address for mail.iol.ie is returned to the "Windows PC."

>>> Some information that might be helpful: Ethereal capturing packets on
>>> Squid's internal interface while running Outlook Send/receive on Linux
>>> client: Windows PC sends DNS query mail.iol.ie Squid replies ICMP
>>> Destination unreachable (port unreachable)

>> For what it's worth, that ICMP message essentially means nothing is
>> listening on the port.  No DNS server running on the port means no IP
>> address for mail.iol.ie is returned to the "Windows PC."

> Well thank you Clifford!  I think I have DNS working now.  When I start a
> send\receive on the Windows machine and capture packets on SuSE's external
> interface I can see that IP addresses for mail.iol.ie and pop.iol.ie are
> being resolved, up to a certain point.  I also see from netstat that the
> SuSE machine is listening to port 53 on TCP only, on both external and
> internal interfaces, but not on UDP. Is this a good thing?

> I'm still at a loss to understand what's going on.  I honestly amn't a
> networking guru by any means but I've learned so much over the past week
> trying to figure this out!  That's why I put the Linux system together --
> to learn!!  I really would appreciate someone helping me resolve my email
> and news issues though!!

>> For what it's worth, that ICMP message essentially means nothing is
>> listening on the port.  No DNS server running on the port means no IP
>> address for mail.iol.ie is returned to the "Windows PC."
> Well thank you Clifford!  I think I have DNS working now.  When I start a
> send\receive on the Windows machine and capture packets on SuSE's
> external interface I can see that IP addresses for mail.iol.ie and
> pop.iol.ie are being resolved, up to a certain point.  I also see from
> netstat that the SuSE machine is listening to port 53 on TCP only, on both
> external and internal interfaces, but not on UDP. Is this a good thing?