[Shorewall-users] Weird NAT issue

[Kade W. Hampson]

Hey guys,



I have been having an issue with one of my servers for a couple weeks, and
it has me absolutely stumped.



So I use shorewall on the router that does all my cross-subnet routing.

Unfortunately one of my servers (192.168.0.3) is not able to communicate
with any other subnets, including WAN.

None of my other PC/Servers seem to have the issue.

My rules are setup so that all ports are open for that IP to anywhere



I am not quite sure if this is a shorewall issue as such, but as the
question I asked on ServerFault
<http://serverfault.com/questions/838550/windows-server-2012-no-communicatio
n-to-other-subnets> has come back black, I thought it was worth a shot.



Regards,

Kade W. Hampson

[Robert K Coffman Jr. -Info From Data Corp.]

Post by Kade W. Hampson
Unfortunately one of my servers (192.168.0.3) is not able to communicate
with any other subnets, including WAN.

Kade,

If 192.168.0.2 is working fine and 192.168.0.3 can communicate to its
own subnet with no issue, I'd check the default gateway on 192.168.0.3.

- Bob

[kadham1]

I have checked the default gateway and routing table on 192.168.0.3, and it is correct....
I am getting log events on my router/firewall about Martian connections from that address?
I use 192.168.0.3 as my Remote Gateway Server and even though it can't access the internet, the Gateway Server is still running like it should be? 


Sent from my SAMSUNG Galaxy S7 on the Telstra Mobile Network

Post by Kade W. Hampson
Unfortunately one of my servers (192.168.0.3) is not able to communicate
with any other subnets, including WAN.

Kade,

If 192.168.0.2 is working fine and 192.168.0.3 can communicate to its
own subnet with no issue, I'd check the default gateway on 192.168.0.3.

- Bob

[Robert K Coffman Jr. -Info From Data Corp.]

Post by kadham1
I am getting log events on my router/firewall about Martian connections
from that address?

This would seem to indicate that it is not plugged into what you think
it is plugged into - do those errors show what interface they are hitting?

- Bob

[kadham1]

No it doesn't unfortunately, but that being said it is on the same VLAN as all machines on 192.168.0.0/24 so if that was the case then none of the machines would be working


Sent from my SAMSUNG Galaxy S7 on the Telstra Mobile Network

Post by kadham1
I am getting log events on my router/firewall about Martian connections
from that address?

This would seem to indicate that it is not plugged into what you think
it is plugged into - do those errors show what interface they are hitting?

- Bob

[Ryan Joiner]

Post by kadham1
No it doesn't unfortunately, but that being said it is on the same VLAN
as all machines on 192.168.0.0/24 so if that was the case then none of
the machines would be working
Sent from my SAMSUNG Galaxy S7 on the Telstra Mobile Network
-------- Original message --------
From: "Robert K Coffman Jr. -Info From Data Corp."
Date: 21/3/17 2:23 am (GMT+10:00)
Subject: Re: [Shorewall-users] Weird NAT issue

Post by kadham1
I am getting log events on my router/firewall about Martian connections
from that address?

This would seem to indicate that it is not plugged into what you think
it is plugged into - do those errors show what interface they are hitting?
- Bob
------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most

Martians usually don't lie. Something is not coming in to the router
correctly. I see the martians are coming on eth0. How do you have eth0
configured? (Sorry if I missed that somewhere). Are you tagging on it
or just have it through the switch untagged?

- Ryan

[kadham1]

I totally missed that, eth0 is my external/wan interface on the router, but it is VLANed to stop any communication with it unless going through the router.


Sent from my SAMSUNG Galaxy S7 on the Telstra Mobile Network

Post by kadham1
No it doesn't unfortunately, but that being said it is on the same VLAN
as all machines on 192.168.0.0/24 so if that was the case then none of
the machines would be working
Sent from my SAMSUNG Galaxy S7 on the Telstra Mobile Network
-------- Original message --------
From: "Robert K Coffman Jr. -Info From Data Corp."
Date: 21/3/17 2:23 am (GMT+10:00)
Subject: Re: [Shorewall-users] Weird NAT issue

Post by kadham1
I am getting log events on my router/firewall about Martian connections
from that address?

This would seem to indicate that it is not plugged into what you think
it is plugged into - do those errors show what interface they are hitting?
- Bob
------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most

Martians usually don't lie.  Something is not coming in to the router
correctly.  I see the martians are coming on eth0.  How do you have eth0
configured? (Sorry if I missed that somewhere).  Are you tagging on it
or just have it through the switch untagged?

- Ryan

[Ryan Joiner]

Post by kadham1
I totally missed that, eth0 is my external/wan interface on the router,
but it is VLANed to stop any communication with it unless going through
the router.

Crazy! Somehow packets are arriving on that interface and thus.. it
ain't gonna work... :)

[kadham1]

If my server was bypassing it's VLAN configuration it wouldn't be able to ping any other devices on the 192.168.0/24 subnet.So this leads me to the only device that could be causing the issue, my firewall.Could it be some bug to do with the MAC address of my server? I have a cron job to update the OS every night, so possibly a rouge update?

Post by kadham1
I totally missed that, eth0 is my external/wan interface on the router,
but it is VLANed to stop any communication with it unless going through
the router.

Crazy!  Somehow packets are arriving on that interface and thus.. it
ain't gonna work... :)

[Ryan Joiner]

Post by kadham1
If my server was bypassing it's VLAN configuration it wouldn't be able
to ping any other devices on the 192.168.0/24 subnet.
So this leads me to the only device that could be causing the issue, my
firewall.
Could it be some bug to do with the MAC address of my server? I have a
cron job to update the OS every night, so possibly a rouge update?
-------- Original message --------
Date: 22/3/17 1:59 am (GMT+10:00)
Subject: Re: [Shorewall-users] Weird NAT issue

What does your eth0 connect to? Is it on the same switch but supposed
to be on a different VLAN?

[kadham1]

It's on the same switch, but I have double checked the VLANs and they are correct


Sent from my SAMSUNG Galaxy S7 on the Telstra Mobile Network

Post by kadham1
If my server was bypassing it's VLAN configuration it wouldn't be able
to ping any other devices on the 192.168.0/24 subnet.
So this leads me to the only device that could be causing the issue, my
firewall.
Could it be some bug to do with the MAC address of my server? I have a
cron job to update the OS every night, so possibly a rouge update?
-------- Original message --------
Date: 22/3/17 1:59 am (GMT+10:00)
Subject: Re: [Shorewall-users] Weird NAT issue

What does your eth0 connect to?  Is it on the same switch but supposed
to be on a different VLAN?