redhat 8.0 as router

[rioguia]

i cannot get a connection to my dsl on my redhat 8.0 box. i have a current smoothwall firewall / router that works great with my dsl connection. smoothwall is great but i need to add some DNS features that are available on the gpl version of the software. i only mention the smoothwall because it works fine by just assigning the correct IP's (this is not a PPOE connection with user signon and password). i have installed Redhat 8.0, using the "router" install package. i am configuring the network card by hand. i attempted this several times with different configurations. the current configuration is below. no firewall was installed.

netconfig to assign:
xxx.xxx.xxx.xxx (where xxx = static IP assigned by my DSL provider)
netmask 255.255.255.0
DNS server = zzz.zzz.zzz.zzz
gateway = yyy.yyy.yyy.yyy

my routing table looks like a perfect three line system

xxx.xxx.xxx.0 to 0.0.0.0
127.0.0.0 to 0.0.0.0
0.0.0.0 to yyy.yyy.yyy.yyy

in spite of this, i can't ping yyy.yyy.yyy.yyy

[grey_pilgrim]

Check your subnet mask. Most ISPs I have worked with for DSL have a different mask. 255.255.255.0 covers a whole lotta addresses!
On my home DSL of 209.x.x.34 I have a mask of 255.255.255.252 giving me only 2 hosts, myself (.34) and their gateway (.33), on the subnet My subnetwork ID is .32 and broadcast is .35
This gives the isp better granularity.

My buddy a couple miles away is using the same DSLAM, and has .54 and a gateway of .33 We can communicate, but not sniff each other's network. With a 255.255.255.0 mask we would be on the same subnet and I would be able to peruse his packets with Etherial.
By changing the subnet mask you are changing the broadcast address of your subnet.

GP

[rioguia]

my smoothwall router's eth2, which connects to the internet and through which I am posting has the exact same netmask setting.

[rioguia]

but just to be sure, i checked with my ISP and my IP and subnet mask, gateway and dns server settings are correct. this seems to eliminate all the sensible mistakes. any others?

[Rickdog]

Did you restart the modem after logging on?

[rioguia]

yes i did thinking that it might be doing some hardware address caching. as it turns out, i later learned from my ISP that my "modem" is just a simple bridge so there isn't much going on there.

[rioguia]

thanks for all the suggestions. following the suggestion of another user, i determined that the problem was rather simple. redhat assigned nic aliases (eth0, etc) to my nics different from those of smoothwall. therefore, my dsl connection was no longer on eth2. a simple reassignment of the nic aliases allowed the router to access the internet. now I can dual boot the router using my smoothwall as my main router until i learn how to make my redhat router use network address translation to share the internet connection, IP tables, and provide dns services for my private domain.