Bug 230755

Summary: natd sends wrong sequence number when a retransmitted PASV packet comes in
Product: Base System Reporter: longwitz
Component: binAssignee: freebsd-ipfw mailing list <ipfw>
Status: New ---    
Severity: Affects Some People CC: ae, eugen
Priority: --- Keywords: patch
Version: 10.4-STABLE   
Hardware: Any   
OS: Any   
Attachments:
Description Flags
Patch for libalias to solve a natd problem none

Description longwitz 2018-08-19 19:06:02 UTC
Created attachment 196357 [details]
Patch for libalias to solve a natd problem

If natd must send out a retransmitted "227 Entering Passive Mode" message then sometimes the sequncenumber of the generated packet is wrong breaking the tcp connection. Details are explained in

   https://lists.freebsd.org/pipermail/freebsd-net/2018-August/051290.html

The attached patch for FreeBSD 10 solves the problem for me and works also for newer FreeBSD versions.