Date: Fri, 28 Aug 1998 11:15:27 -0400 From: sbabkin@dcn.att.com To: stefan@promo.de, hm@kts.org Cc: freebsd-hackers@FreeBSD.ORG Subject: RE: TCP checksum errors resulting from IP addr change Message-ID: <C50B6FBA632FD111AF0F0000C0AD71EEFF8BBF@dcn71.dcn.att.com>
next in thread | raw e-mail | index | archive | help
> -----Original Message----- > From: Stefan Bethke [SMTP:stefan@promo.de] > > On Fre, 28. Aug 1998 9:22 Uhr +0200 Hellmuth Michaelis <hm@kts.org> > wrote: > > > I'm trying to debug a strange effect occuring on a sync PPP ISDN > interface > > which is used to connect to a Cisco 1003 (on 192.76.124.10). > > > > To get an address dynamically from the remote side, the local PPP > inter- > > face (on 2.2.5-RELEASE) is set up with: > > > > ifconfig isppp0 link1 0.0.0.0 192.76.124.10 netmask 0xffffffff > debug > > > > Now i telnet to 192.76.124.10 and the link gets established but the > telnet > > session doesn't. > Sorry for a stupid question, but may it be related somehow to the header compression mode ? I'm not sure about the PPP compression but for SLIP these symptoms would clearly indicate that one side is working with compression while another one is working without compression. The SLIP compression works on a per-connection basis, so datagram packets and the TCP SYN packets are always not compressed - so ping works and you can establish the connection, but following TCP packets have their headers compressed by removing the redundant information that can be restored from previous TCP packets, so they would appear broken if the other side works in other mode. It may be that PPP is using something like this (and it also has 2 different compression modes). -Sergey To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?C50B6FBA632FD111AF0F0000C0AD71EEFF8BBF>