Andre Oppermann wrote: > 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 dr.clau_at_gmail.com
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