{"id":603,"date":"2011-09-27T05:19:05","date_gmt":"2011-09-27T09:19:05","guid":{"rendered":"http:\/\/www.xavignu.com\/?p=603"},"modified":"2011-09-28T05:15:07","modified_gmt":"2011-09-28T09:15:07","slug":"connecting-gns3-simulator-to-the-internet","status":"publish","type":"post","link":"https:\/\/www.xavignu.com\/?p=603","title":{"rendered":"Connecting GNS3 simulator to the Internet"},"content":{"rendered":"

I know it’s been a while. No, I haven’t been lost, in Guantanamo or similar. I was just too lazy\/busy to write a post. But luckily I’m back. \ud83d\ude42<\/p>\n

Today I’m going to write about how to connect GNS3<\/a> lab to the internet. For this we are going to have to create a tap interface on our Debian<\/a> box. First thing would be to install the uml-utilities on your Debian box.<\/p>\n

[10:52:55] xavi@lstkco14073: ~ $ sudo aptitude search uml-utilities<\/b>
\ni uml-utilities            – User-mode Linux (utility programs)
\n[10:53:00] xavi@lstkco14073: ~ $ <\/p>\n

Now install with:<\/p>\n

[10:53:00] xavi@lstkco14073: ~ $ sudo aptitude install uml-utilities<\/b><\/p>\n

Once uml-utilities is installed you can execute the following script to bring up a tap interface.<\/p>\n

[code lang=”bash”]
\n#!\/bin\/bash
\nsudo tunctl -t tap0 -u `whoami`
\nsudo ifconfig tap0 192.168.1.1 netmask 255.255.255.252 up
\n\/sbin\/ifconfig tap0
\n[\/code]<\/p>\n

[11:02:06] xavi@lstkco14073: ~ $ sh tap0<\/b>
\nSet ‘tap0’ persistent and owned by uid 1000
\ntap0 Link encap:Ethernet HWaddr 5e:3c:9d:d8:ff:9a
\n inet addr:192.168.1.1 Bcast:192.168.1.255 Mask:255.255.255.252
\n UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
\n RX packets:0 errors:0 dropped:0 overruns:0 frame:0
\n TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
\n collisions:0 txqueuelen:500
\n RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)<\/p>\n

[11:02:17] xavi@lstkco14073: ~ $<\/p>\n

We would need to connect this tap interface to the GNS3 simulation. We also would need to configure iptables to allow routing on the Debian<\/a> box. For that we need to execute the following script.<\/p>\n

[code lang=”bash”]
\n#!\/bin\/bash
\n# Script to enable IP packet forwarding and NAT
\n#
\n# eth0 is Internet connected interface<\/p>\n

# Enable IP Forwarding
\necho 1 > \/proc\/sys\/net\/ipv4\/ip_forward<\/p>\n

# Clean up iptables
\niptables -F
\niptables -t nat -F
\niptables -X<\/p>\n

# Enable IP MASQUERADING\/NAT
\niptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE<\/p>\n

# Set firewall policies
\niptables -P FORWARD ACCEPT
\niptables -P OUTPUT ACCEPT<\/p>\n

# Allow all connections not from wlan0
\niptables -A INPUT ! -i eth0 -j ACCEPT<\/p>\n

# Allow all ICMP connections
\niptables -A INPUT -p ICMP -j ACCEPT<\/p>\n

# Allow all already established connections
\niptables -A INPUT -m state –state ESTABLISHED,RELATED -j ACCEPT
\n[\/code]<\/p>\n

In our next post we would configure the GNS3 simulator. Comments are always welcome.<\/p>\n","protected":false},"excerpt":{"rendered":"

I know it’s been a while. No, I haven’t been lost, in Guantanamo or similar. I was just too lazy\/busy to write a post. But luckily I’m back. \ud83d\ude42 Today I’m going to write about how to connect GNS3 lab to the internet. For this we are going to have to create a tap interface […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"spay_email":"","jetpack_publicize_message":"","jetpack_is_tweetstorm":false,"jetpack_publicize_feature_enabled":true},"categories":[3],"tags":[30,56,22,6,23,70],"jetpack_featured_media_url":"","jetpack_publicize_connections":[],"jetpack_shortlink":"https:\/\/wp.me\/pTQgt-9J","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.xavignu.com\/index.php?rest_route=\/wp\/v2\/posts\/603"}],"collection":[{"href":"https:\/\/www.xavignu.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.xavignu.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.xavignu.com\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.xavignu.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=603"}],"version-history":[{"count":21,"href":"https:\/\/www.xavignu.com\/index.php?rest_route=\/wp\/v2\/posts\/603\/revisions"}],"predecessor-version":[{"id":623,"href":"https:\/\/www.xavignu.com\/index.php?rest_route=\/wp\/v2\/posts\/603\/revisions\/623"}],"wp:attachment":[{"href":"https:\/\/www.xavignu.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=603"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.xavignu.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=603"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.xavignu.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=603"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}