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I'm currently setting up my server. I use proxmox which similar to vmware. Important thing to know is that i only have 1 external IP address. On my server, I forward port 80 and 443 to virtual host apache using this command :

iptables -t nat -A PREROUTING -p tcp --dport 80 -j DNAT --to
iptables -t nat -A PREROUTING -p tcp --dport 443 -j DNAT --to

My network is also linked with :

iptables -t nat -D POSTROUTING -s '' -o eth0 -j MASQUERADE

Now the problem is that if I do redirect port 80 & 443 this way, apt-get throws 404 Error when i use it from a VM (behind my gate).

How can I redirect port to my VM by having still apt-get working ? What am I doing wrong ?


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migrated from Feb 14 '13 at 15:56

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2 Answers 2

up vote 0 down vote accepted

You redirect ALL packets to port 80 and 443 to your guest, including its own packets. Add a

-i eth0 

condition to your DNAT rules.

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I don't see why that shall be a problem. If e.g. tries to access the webserver then it will probably try to connect to the external address so this packet from eth1(?) must be DNATted to, too. –  Hauke Laging Feb 14 '13 at 16:14

Can you check (with tcpdump) what happens on the webserver? I assume that such a rule is missing (assuming eth1 is your internal interface):

iptables -t nat -A PREROUTING -i eth1 -o eth1 -j SNAT --to $INTERNAL_GATEWAY_IP

Without this the client tries to connect to, the gateway deflects the packet to, the webserver sees a connection from the client (e.g. thus sends its reply to, and the client having sent to and getting a reply from just goes "WTF?"... But with SNAT the webserver responds to the gateway, the gateway rewrites both source and destination address and everyone's happy.

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