Hello List, Could someone enlighten me as to when FreeBSD 6.3 does UDP packet reassembly? I am having a problem where I am getting a fragmented udp packet (2 pieces) everthing is fine if I get the first frag first. but if the second frag comes first then both fragments get dropped. I am using ipfilter and a bimap to redirect these packets to a host inside of the FreeBSD box, so I suspicion it is ipfilter causing the drops. I know, I know 6.3 is ancient history, but any insight would be appreciated. Thank, Steve -- "They that give up essential liberty to obtain temporary safety, deserve neither liberty nor safety." (Ben Franklin) "The course of history shows that as a government grows, liberty decreases." (Thomas Jefferson)
On Jul 28, 2011, at 12:01 PM, Stephen Clark wrote:> Could someone enlighten me as to when FreeBSD 6.3 does UDP packet reassembly?Packet reassembly is done at the IP layer, not the UDP layer. Normally, reassembly is performed on the destination host, but routers or firewalls along the path conceivably might also reassemble packets.> I am having a problem where I am getting a fragmented udp packet (2 pieces) everthing is > fine if I get the first frag first. but if the second frag comes first then both fragments get dropped. > > I am using ipfilter and a bimap to redirect these packets to a host inside of the FreeBSD box, > so I suspicion it is ipfilter causing the drops. > > I know, I know 6.3 is ancient history, but any insight would be appreciated.It's probably the firewall dropping the traffic, yes-- running tcpdump on the firewall versus the destination host would confirm this. Something like "keep frags" on your pass rules would help if it is ipfilter... Regards, -- -Chuck
On 7/28/2011 3:01 PM, Stephen Clark wrote:> Hello List, > > Could someone enlighten me as to when FreeBSD 6.3 does UDP packet > reassembly? > > I am having a problem where I am getting a fragmented udp packet (2 > pieces) everthing is > fine if I get the first frag first. but if the second frag comes first > then both fragments get dropped. > > I am using ipfilter and a bimap to redirect these packets to a host > inside of the FreeBSD box, > so I suspicion it is ipfilter causing the drops.Not sure, but you try pf instead ? And use scrub log fragment reassemble ---Mike> > I know, I know 6.3 is ancient history, but any insight would be > appreciated. > > Thank, > Steve >-- ------------------- Mike Tancsa, tel +1 519 651 3400 Sentex Communications, mike@sentex.net Providing Internet services since 1994 www.sentex.net Cambridge, Ontario Canada http://www.tancsa.com/
Hello List, Didn't see this show up in the mailing list so I am resending. Could someone enlighten me as to when FreeBSD 6.3 does UDP packet reassembly? I am having a problem where I am getting a fragmented udp packet (2 pieces) everthing is fine if I get the first frag first. but if the second frag comes first then both fragments get dropped. I am using ipfilter and a bimap to redirect these packets to a host inside of the FreeBSD box, so I suspicion it is ipfilter causing the drops. I know, I know 6.3 is ancient history, but any insight would be appreciated. Thank, Steve -- "They that give up essential liberty to obtain temporary safety, deserve neither liberty nor safety." (Ben Franklin) "The course of history shows that as a government grows, liberty decreases." (Thomas Jefferson)