OT: Weird routing issues
I apologize for asking this question here, but I'm not sure where
better to ask it. If people would like to respond via private mail or
direct me to a better group to ask, I'd appreciate it.
I work for a small ISP that uses Debian servers (here the on-topicness
ends). We've recently gotten an ADSL connection from SBC which we've
connected to a Cisco 3640 router: the ADSL bridge is connected to an
ethernet port on the router on which we run a pppoe client. The pppoe
interface is set as the default gateway on the router and we're using
a subnet of the IP addresses we've been assigned from SBC on another
of the router's ethernet interfaces. If I hook up a laptop (or other
equipment) to that ethernet and configure it with an IP in that subnet
with the router as its default gateway, everything works just as I
would expect it to ... mostly. The problem is that a few web sites
are horribly slow (notably www.ebay.com, but we've found a couple of
others).
If, from the laptop, I telnet to www.ebay.com on port 80, type 'GET
/', and hit enter, then Ebay's front page comes back, but
packet-by-packet, with about 15 seconds between packets. If I do the
same thing from the router itself, I get nothing back, and after a few
seconds, www.ebay.com closes the connection. If, however, I hit enter
twice after typing 'GET /' on the router, I get the whole page
immediately. Other web sites come back immediately on both the laptop
and the router. Traceroutes and tcptraceroutes to www.ebay.com and
other web servers don't seem to differ significantly. But if I switch
to a different Internet connection (a T1 from Sprint) on a different
router, all the problems go away. Also, we have a few ADSL customers
connected through the 3640 router (their PPPoE sessions terminate
there), they use the SBC DSL line to get to the Internet, and have no
problems at all.
I've gone over the configuration of the router a number of times, and
have yet to see anything out of order. I'm nearly at my wits' end,
and I'd appreciate any suggestions I get.
Sorry, again, for the off-topic post,
Micah
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