I have setup Redhat 7.1 to be a gateway for my 2 win98 systems. It works great, except for 2 exceptions. There is one mail server that I get mail from that I can connect to, but it won't download any messages - it just hangs when receiving, and then times out. There is also one web site that I cannot hit. I get the background colours, but no text or graphics on the page. It is an SSL site (my banking site), and I can hit other SSL sites, like the Red Hat Network site.

Both of these problems go away, when I hook my modem up to my Win 98 PC, and use the dsl software that my ISP provided (Enternet)

If I can get any insite into this problem, I'd appreciate it.

P.S. We also have DSL in a couple of the schools in the division where I work as a tech, and we use a similar router there (coyote linux), and I have the same problem, although that has not become an issue there yet. So I know that it is not my switch, or cabling or anything like that.

Thanks so much for the help that I'm going to get

OOPS....forgot to mention, I'm using Roaring Penguin's pppoe to connect my Linux system to my dsl provider.

You should set the mtu of the windows machine to 1452 and the port on the linux machine they connect to to 1452.

Then it will work fine.

WHY?

pppoe is set to 1492 max


setting it to 1452 will give you enough bites for ICMP and TCP

HOW

ifconfig eth1 mtu 1452


windows


registry edit, you can find info, tools, and scripts at dslreports.com


each version of windows is a little different.


Also check into setting the TCP window size while your at it.

the alternative to this is to use clamp mss in roaring penguin, but I would do it the other way. AND Turn of Clamp MSS


There is more info on this from micro$oft but it is not very detailed, other than it is required when running ICS on adsl

Thanks for the response, I actually found a fix on Roaring Penguin's site (I don't know why I missed it before)

here's an excerp from their site...they recommend using the CLAMPMSS I changed my value to 1312, and now I can hit everything just fine.

You said something about using a different fix...well, I have messed with my MTU settings, and while that improved performance, it did nothing for these couple of sites that I couldn't hit...

Thanks again!


The excerp (for those that might need it):

There is probably a buggy router or firewall between you and the Web server.
One possible workaround: In /etc/ppp/pppoe.conf, find the line which reads:

CLAMPMSS=1412

Try lowering the 1412 until it works (go down in steps of 100 or so.) Each
time you lower the value, you have to restart your connection like this:

adsl-stop; adsl-start

This should work around buggy routers which do not support Path MTU discovery.