DHCP server bug?

mikael
Full Member

Posts: 39

DHCP server bug? Sept 22, 2015 8:47:06 GMT

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Post by mikael on Sept 22, 2015 8:47:06 GMT

Hi,

When smallwall DHCP server offers DNS servers to the client and "Enable DNS forwarder" is enabled then then client recieves TWO DNS servers from smallwall:
1) the LAN address of smallwall (fine! tha's what we want)
2) The second ISP DNS server. (not fine! we don't want that!)

Perhaps and old bug or perhaps not a bug at all. I would expect smallwall to only offer ONE DNS server (the smallwall LAN address) if "Enable DNS forwarder" is enabled.

Last Edit: Sept 22, 2015 8:47:56 GMT by mikael

Lee Sharp
Administrator

Posts: 522

DHCP server bug? Sept 22, 2015 17:39:35 GMT

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Post by Lee Sharp on Sept 22, 2015 17:39:35 GMT

Hmmm... I am not able to see this. (And I looked at a few installations for it. I set "Enable DNS forwarder" for all my clients.) What operating system is seeing this? Would you feel comfortable sending me a copy of you config, or one with no passwords from status.php?

Last Edit: Sept 22, 2015 17:39:53 GMT by Lee Sharp

mikael
Full Member

Posts: 39

DHCP server bug? Sept 25, 2015 10:33:46 GMT

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Post by mikael on Sept 25, 2015 10:33:46 GMT

I am sorry! I got very confused. I have been playing around and testing the L2TP VPN stuff and I was connected to the LAN via L2TP VPN when I noticed that smallwall is offering two DNS resolvers to its clients. The first is smallwall DNS forwarder (ok) the second is one of the DNS servers I have specified in the "General setup" page.

Does this make more sense?

I have seen this behaviour on different clients (MacOS, Linux).
I have also seen this when using PPTP VPN.

Perhaps it has nothing to do with the DHCP server.

Last Edit: Sept 25, 2015 10:34:40 GMT by mikael

Lee Sharp
Administrator

Posts: 522

DHCP server bug? Sept 25, 2015 17:22:12 GMT

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Post by Lee Sharp on Sept 25, 2015 17:22:12 GMT

Ah... That is normal and intended. Sometimes DNS requests can go into a black hole when VPN is up, and the firewall can not be reached. Having a backup DNS server can hide this issue. Not the best solution, but one that worked well at the time.

Post by mikael on Sept 22, 2015 8:47:06 GMT

Post by Lee Sharp on Sept 22, 2015 17:39:35 GMT

Post by mikael on Sept 25, 2015 10:33:46 GMT

Post by Lee Sharp on Sept 25, 2015 17:22:12 GMT

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