Why does my NAT setup only work properly from time to time?
Homework assignment...
There are 3 computers in a local network: 192.168.0.185 (the 'client'), 192.168.0.129 (the 'gateway') and 192.168.0.81 (the 'server'). The 'server' is running a HTTP server, so typing 192.168.0.81 in a browser's address bar from any of the other two computers displays a webpage.
The assignment is to set up NAT in the so-called 'gateway' in such a way that typing its IP address (192.168.0.129) in the 'client's browser will display the webpage served by the 'server'. This is my solution attempt:
echo 1 > /proc/sys/net/ipv4/ip_forward
iptables -t nat -A PREROUTING -p tcp -d 192.168.0.129 --dport 80 -j DNAT --to 192.168.0.81:80
iptables -t nat -A POSTROUTING -p tcp -d 192.168.0.81 --dport 80 -j SNAT --to 192.168.0.129:80
This (I hoped) would make the 'gateway' redirect requests made to it to the 'server' (DNAT) while substituting source address of the request to its own so that the 'server' will correctly send the response through the 'gateway' and not straightly to the 'client' (SNAT).
I typed the 'gateway's IP in the 'client's browser's address bar. Hooray! I saw the webpage! I thought I was done!
Except I wasn't. I then reloaded the page on the 'client'. And I got timeout error. I reloaded the page once again. Timeout again. I waited a teeny tiny bit and reloaded once again. This page the webpage was served correctly. So I reloaded for the final time and... timeout.
This confuses me. It seems that once a page is served things stop working for a while. Why is that happening? Where is my mistake?
I should note that typing the 'server's address in the 'client's browser (as opposed to typing the 'gateway's address) does not cause such problems.
networking iptables nat
asked 15 mins ago
gaazkamgaazkam
3581514
add a comment |
Homework assignment...
There are 3 computers in a local network: 192.168.0.185 (the 'client'), 192.168.0.129 (the 'gateway') and 192.168.0.81 (the 'server'). The 'server' is running a HTTP server, so typing 192.168.0.81 in a browser's address bar from any of the other two computers displays a webpage.
The assignment is to set up NAT in the so-called 'gateway' in such a way that typing its IP address (192.168.0.129) in the 'client's browser will display the webpage served by the 'server'. This is my solution attempt:
echo 1 > /proc/sys/net/ipv4/ip_forward
iptables -t nat -A PREROUTING -p tcp -d 192.168.0.129 --dport 80 -j DNAT --to 192.168.0.81:80
iptables -t nat -A POSTROUTING -p tcp -d 192.168.0.81 --dport 80 -j SNAT --to 192.168.0.129:80
This (I hoped) would make the 'gateway' redirect requests made to it to the 'server' (DNAT) while substituting source address of the request to its own so that the 'server' will correctly send the response through the 'gateway' and not straightly to the 'client' (SNAT).
I typed the 'gateway's IP in the 'client's browser's address bar. Hooray! I saw the webpage! I thought I was done!
Except I wasn't. I then reloaded the page on the 'client'. And I got timeout error. I reloaded the page once again. Timeout again. I waited a teeny tiny bit and reloaded once again. This page the webpage was served correctly. So I reloaded for the final time and... timeout.
This confuses me. It seems that once a page is served things stop working for a while. Why is that happening? Where is my mistake?
I should note that typing the 'server's address in the 'client's browser (as opposed to typing the 'gateway's address) does not cause such problems.
networking iptables nat
asked 15 mins ago
gaazkamgaazkam
3581514
could be a problem with the web server
– jsotola
12 mins ago
@jsotola I don't think so; please see the edited question.
– gaazkam
9 mins ago
why are you accessing the webpage by using the gateway address?
– jsotola
5 mins ago
@jsotola Because the assignment says I have to configure the 'gateway' in such a way to make this possible.
– gaazkam
5 mins ago
add a comment |
Homework assignment...
There are 3 computers in a local network: 192.168.0.185 (the 'client'), 192.168.0.129 (the 'gateway') and 192.168.0.81 (the 'server'). The 'server' is running a HTTP server, so typing 192.168.0.81 in a browser's address bar from any of the other two computers displays a webpage.
The assignment is to set up NAT in the so-called 'gateway' in such a way that typing its IP address (192.168.0.129) in the 'client's browser will display the webpage served by the 'server'. This is my solution attempt:
echo 1 > /proc/sys/net/ipv4/ip_forward
iptables -t nat -A PREROUTING -p tcp -d 192.168.0.129 --dport 80 -j DNAT --to 192.168.0.81:80
iptables -t nat -A POSTROUTING -p tcp -d 192.168.0.81 --dport 80 -j SNAT --to 192.168.0.129:80
This (I hoped) would make the 'gateway' redirect requests made to it to the 'server' (DNAT) while substituting source address of the request to its own so that the 'server' will correctly send the response through the 'gateway' and not straightly to the 'client' (SNAT).
I typed the 'gateway's IP in the 'client's browser's address bar. Hooray! I saw the webpage! I thought I was done!
Except I wasn't. I then reloaded the page on the 'client'. And I got timeout error. I reloaded the page once again. Timeout again. I waited a teeny tiny bit and reloaded once again. This page the webpage was served correctly. So I reloaded for the final time and... timeout.
This confuses me. It seems that once a page is served things stop working for a while. Why is that happening? Where is my mistake?
I should note that typing the 'server's address in the 'client's browser (as opposed to typing the 'gateway's address) does not cause such problems.
networking iptables nat
asked 15 mins ago
gaazkamgaazkam
3581514
Homework assignment...
There are 3 computers in a local network: 192.168.0.185 (the 'client'), 192.168.0.129 (the 'gateway') and 192.168.0.81 (the 'server'). The 'server' is running a HTTP server, so typing 192.168.0.81 in a browser's address bar from any of the other two computers displays a webpage.
The assignment is to set up NAT in the so-called 'gateway' in such a way that typing its IP address (192.168.0.129) in the 'client's browser will display the webpage served by the 'server'. This is my solution attempt:
echo 1 > /proc/sys/net/ipv4/ip_forward
iptables -t nat -A PREROUTING -p tcp -d 192.168.0.129 --dport 80 -j DNAT --to 192.168.0.81:80
iptables -t nat -A POSTROUTING -p tcp -d 192.168.0.81 --dport 80 -j SNAT --to 192.168.0.129:80
This (I hoped) would make the 'gateway' redirect requests made to it to the 'server' (DNAT) while substituting source address of the request to its own so that the 'server' will correctly send the response through the 'gateway' and not straightly to the 'client' (SNAT).
I typed the 'gateway's IP in the 'client's browser's address bar. Hooray! I saw the webpage! I thought I was done!
Except I wasn't. I then reloaded the page on the 'client'. And I got timeout error. I reloaded the page once again. Timeout again. I waited a teeny tiny bit and reloaded once again. This page the webpage was served correctly. So I reloaded for the final time and... timeout.
This confuses me. It seems that once a page is served things stop working for a while. Why is that happening? Where is my mistake?
I should note that typing the 'server's address in the 'client's browser (as opposed to typing the 'gateway's address) does not cause such problems.
networking iptables nat
networking iptables nat
asked 15 mins ago
gaazkamgaazkam
3581514
asked 15 mins ago
gaazkamgaazkam
3581514
edited 9 mins ago
gaazkam
asked 15 mins ago
gaazkamgaazkam
3581514
asked 15 mins ago
gaazkamgaazkam
3581514
asked 15 mins ago
gaazkamgaazkam
3581514
3581514
could be a problem with the web server
– jsotola
12 mins ago
@jsotola I don't think so; please see the edited question.
– gaazkam
9 mins ago
why are you accessing the webpage by using the gateway address?
– jsotola
5 mins ago
@jsotola Because the assignment says I have to configure the 'gateway' in such a way to make this possible.
– gaazkam
5 mins ago
add a comment |
could be a problem with the web server
– jsotola
12 mins ago
@jsotola I don't think so; please see the edited question.
– gaazkam
9 mins ago
why are you accessing the webpage by using the gateway address?
– jsotola
5 mins ago
@jsotola Because the assignment says I have to configure the 'gateway' in such a way to make this possible.
– gaazkam
5 mins ago
could be a problem with the web server
– jsotola
12 mins ago
could be a problem with the web server
– jsotola
12 mins ago
@jsotola I don't think so; please see the edited question.
– gaazkam
9 mins ago
@jsotola I don't think so; please see the edited question.
– gaazkam
9 mins ago
why are you accessing the webpage by using the gateway address?
– jsotola
5 mins ago
why are you accessing the webpage by using the gateway address?
– jsotola
5 mins ago
@jsotola Because the assignment says I have to configure the 'gateway' in such a way to make this possible.
– gaazkam
5 mins ago
@jsotola Because the assignment says I have to configure the 'gateway' in such a way to make this possible.
– gaazkam
5 mins ago
add a comment |
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could be a problem with the web server
– jsotola
12 mins ago
@jsotola I don't think so; please see the edited question.
– gaazkam
9 mins ago
why are you accessing the webpage by using the gateway address?
– jsotola
5 mins ago
@jsotola Because the assignment says I have to configure the 'gateway' in such a way to make this possible.
– gaazkam
5 mins ago