Step Six: Testing external MASQ server to Internet
connectivity
From the MASQ server, ping the external IP address of the MASQ server's
EXTERNAL network interface that is connected to the Internet. This address
might be a Ethernet interface, a PPP interface, etc. connection to your ISP.
If you don't know what this external IP address is, run the Linux command
"/sbin/ifconfig" on the MASQ server itself
to get the Internet address. The output should look something like the
following (we are looking for the IP address of eth0):
------------------------------------
eth0 Link encap:Ethernet HWaddr 00:08:C7:A4:CC:5B
inet addr:12.13.14.15 Bcast:12.13.14.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:6108459 errors:0 dropped:0 overruns:0 frame:0
TX packets:5422798 errors:8 dropped:0 overruns:0 carrier:8
collisions:4675 txqueuelen:100
Interrupt:11 Base address:0xfcf0
------------------------------------ As you can see from the above, the external IP address is "12.13.14.15" for
this example. So, now that you have your IP address after running the
"ipconfig" command, ping your external IP address. This will confirm that the
MASQ server has full network connectivity. The output should look something
like the following (hit Control-C to abort the ping):
-------------------------------------
masq-server# ping 12.13.14.15
PING 12.13.14.15 (12.13.14.15): 56 data bytes
64 bytes from 12.13.14.15: icmp_seq=0 ttl=255 time=0.8 ms
64 bytes from 12.13.14.15: icmp_seq=1 ttl=255 time=0.4 ms
64 bytes from 12.13.14.15: icmp_seq=2 ttl=255 time=0.4 ms
64 bytes from 12.13.14.15: icmp_seq=3 ttl=255 time=0.5 ms
^C
--- 12.13.14.15 ping statistics ---
4 packets transmitted, 4 packets received, 0% packet loss
round-trip min/avg/max = 0.4/0.5/0.8 ms
-------------------------------------
If either of these tests doesn't work, you need to go back and double check
your network cabling and verify that the two network interfaces on the MASQ
server are seen in "dmesg". An example of this output would be the following
towards the END of the "dmesg" command:
-------------------------------------
.
.
PPP: version 2.3.7 (demand dialling)
TCP compression code copyright 1989 Regents of the University of California
PPP line discipline registered.
3c59x.c:v0.99H 11/17/98 Donald Becker
http://cesdis.gsfc.nasa.gov/linux/drivers/
vortex.html
eth0: 3Com 3c905 Boomerang 100baseTx at 0xfe80, 00:60:08:a7:4e:0e, IRQ 9
8K word-wide RAM 3:5 Rx:Tx split, autoselect/MII interface.
MII transceiver found at address 24, status 786f.
Enabling bus-master transmits and whole-frame receives.
eth1: 3Com 3c905 Boomerang 100baseTx at 0xfd80, 00:60:97:92:69:f8, IRQ 9
8K word-wide RAM 3:5 Rx:Tx split, autoselect/MII interface.
MII transceiver found at address 24, status 7849.
Enabling bus-master transmits and whole-frame receives.
Partition check:
sda: sda1 sda2 < sda5 sda6 sda7 sda8 >
sdb:
.
.
-------------------------------------
Also be sure that the cabling is correct (Ethernet: the NICs connecting the
external MASQ server to your ISP has the "link" light lit up). Finally, make
sure that TCP/IP is correctly configured on the MASQed Server as described by
the various Network HOWTOs (URLs can be found in the requirements section for
your
2.4.x kernel in Section 2.6,
2.2.x kernel in Section 2.7, or
2.0.x kernel in Section 2.8).
