Peter Jeremy wrote:
On Sun, 2004-Nov-28 18:43:47 +0200, Claudiu Dragalia-Paraipan wrote:
Since the problem occurs only when I connect to the firewall or to a server behind it, I started to suspect a hardware failure. Could a network card cause such problems ?
A couple of people have mentioned path-MTU problems. I've also bumped into this problem when playing with VLANs where one end of the VLAN trunk doesn't support long frames - an oversize packet will get ignored by the receiver without any error being returned.
If the oversized ethernet frame makes it to the FreeBSD box it will drop the frame in the ethernet hardware or in ether_input() with a message. If you don't get a message on the console you have to look at the driver statistics if it got any oversized frames.
If the switches along the patch can't handle the oversized frame they will simply drop it. No way to work around that.
When the MTU is set to a value below 1500, for example 1450, I get this messages:
Nov 29 23:02:34 firewall kernel: rl0: discard oversize frame (ether type 800 flags 3 len 1466 > max 1464)
Nov 29 23:03:00 firewall kernel: rl0: discard oversize frame (ether type 800 flags 3 len 1514 > max 1464)
... and much many of them.
With MTU 1500 I didn't notice any such message in logs.
So, can I safely assume that the problem occurs because somewhere packets are simply dropped, without any warning ?
-- Claudiu Dragalina-Paraipan [EMAIL PROTECTED]
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