On Mon, 22 Jul 2002, Paul M Foster wrote:
> Situation: Two Red Hat 6.1/6.2 boxes, connected via Cat5 to a hub. One
> box (felix) has a modem connected to it, and dials out to the internet.
> The other box (calvin) wishes to surf via felix. I did some preliminary
> tests....
> 6. So now I get ping answers on calvin, but the waits are bizarre. First
> ping is sub-second. Second is a minute, third is about 90 seconds,
> fourth is about 2-1/2 minutes. I can tell this because ping -v shows the
> sequence numbers of the pings.
Seems like eighty percent of issues are DNS based. Please
retry without DNS -- use ping -n -- do the delays continue ?
> 7. Now, oddly enough, monitoring that same sequence of pings on the ppp0
> interface of felix with tcpdump, the pings come back rapid-fire, one per
> second. So they're going out and coming in properly from felix, but
> calvin isn't getting the responses in the same time frame.
>
> 8. So maybe LAN collisions? Nope. Checked ifconfig, and there were no
> collisions on the ppp0 interface, and only two on the eth0 interface.
or a routing issue --
Please with the modem live, return route -n and
ifconfig
> 9. FWIW, /etc/nsswitch.conf shows "hosts: files dns". /etc/resolv.conf
> shows two nameservers, in the standard "nameserver xxx.xxx.xxx.xxx"
> configuration. /etc/hosts shows all the hosts on the network properly.
>
> So I'm baffled. Why would pings travel via the gateway (felix) at speed,
> return at speed, but take minutes to go back to the originating machine
> from the gateway?
or the ever popular firewalling options in RH 7.1 and later --
which are quite effective ...
-- Russ Herrold
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