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Old 26th September 2013
juslaxnern juslaxnern is offline
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Default BSD not reachable from Internal LAN

Gooood Morning,

I have a webserver running OpenBSD 5.0 with Apache and has been running smooth since built. Well its time to upgrade the hardware and everything was configured appropriately. The issue is:

The original server is accessible from the Outside to DMZ network (NAT rules in place) and also internally ( inside to DMZ ). I swapped out the server (same IP addresses), cleared ARP on the ASA and the server is only accessible from the Outside network. The server is completely blocking all requests internally.

I have determined it is not an ASA issue because the same IP's are in place and once I clear arp, the server responds correctly from the outside. Packet tracer also shows the traffic being permitted. It is very bizarre. My only thoughts were the PF config but I tried disabling that to no effect.

Things that changed:

Upgraded to OpenBSD 5.3 x64
New Physical Server
Apache 1.9.3

Fire away with thoughts!

Thanks!
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Old 26th September 2013
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jggimi jggimi is offline
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Hello, and welcome!

  • You posted this in a FreeBSD subforum. I'll ask one of the admins to move it for you.
  • Did you conduct an upgrade from 5.0 -> 5.1 -> 5.2 -> 5.3? Upgrade directly from 5.0 to 5.3? Reinstall 5.3?
  • Often, the symptoms you describe are caused by improper name resolution in port-forwarded environments. It's so common, there's a section of the PF User's Guide dedicated to it, in a subsection of the Port Forwarding chapter called Redirection and Reflection. Does this apply to your environment? We have no topology information, so this is a guess on my part.
  • If the above does not apply, network diagnostics will be needed. OpenBSD comes with tcpdump(8). Let us know if you need assistance with it.
------

Edited to add:

Since we don't know anything other than what you posted, there's always the possibility of a misconfigured NIC, if you have two or more NICs used with the OpenBSD server. The output of:

$ ifconfig -A

may help us, if that's the case.

Last edited by jggimi; 26th September 2013 at 06:47 PM. Reason: typo, additional comments
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Old 27th September 2013
J65nko J65nko is offline
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When a DMZ configureation does not work, it usually is the routing. The server in the DMZ needs to have the default route set to the DMZ NIC of the firewall. Of course the NAT needs to handle both the external IP <--> DMZ and internal LAN <--> DMZ traffic.
What is the output of # netstat -rn -f inet?

If a client on the LAN tries to connect to the DMZ server, does tcpdump on the server show these incoming requests? Do you see the server sending reply packets?

BTW in these cases a network diagram is always helpful
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Old 27th September 2013
juslaxnern juslaxnern is offline
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The upgrade was a swap with new hardware. Old serverA running 5.0. New server running 5.3. The pages pull up fine from the public outside world, but is not accessible from the inside LAN. The routing is confirmed set to the NIC of the FW. The FW HAS to be configured correctly because all of the IP routing works when the old server is in place. I believe it had something to do with PF but it is now disabled. I will try and post tcpdump soon.

Thanks!
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Old 27th September 2013
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jggimi jggimi is offline
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Thank you for the additional information, juslaxnern.

I'm still not clear about a few things. Perhaps you can clarify when you post here again.
  • How many local area networks / NICs does your webserver have connected? I ask because there are many possible "DMZ" topologies.
If only one NIC is used: since PF is disabled your problem is in your local network configuration, and not in OpenBSD. That problem is either routing or domain name address resolution. J65nko mentioned the former, I mentioned the latter.


If two or more NICs are used, you might still have a network configuration problem as above, but you may also have misconfigured one of the NICs.


An ASCII "picture" of your network topology, or a link to a graphic would be helpful. Also helpful would be capturing the output from the ifconfig and route commands that we've both suggested.


You may find the script(1) tool useful for capturing console output for later editing/copying/pasting.


In general, the more information you provide to us, the better we can be at helping you. See this guidance for perfect problem reporting.
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