From Bugzilla Helper: User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4.3) Gecko/20040924 Description of problem: I am experiencing problems connecting from RHEL v3 to any other RHEL v3 machine over IPv6 when the machines in question are on different vlans. The vlans in question are on the same physical Cisco switch (don't know if that matters) and the network is currently configured for IPv4/IPv6 dual-stack. I have experienced this problem when trying to use several different applications (our own version of ssh and ktelnet/krcp, etc), but for the sake of this bug I will just discuss telnet, since it is included with RHEL v3. Specifically, the problem is that I can telnet from a RHEL v3 machine to another RHEL v3 machine without any problems over IPv4. If I try to telnet from a RHEL v3 machine to another RHEL v3 machine over IPv6 the client "hangs" after I have authenticated (i.e. I never get a shell prompt). IPv6 connections work fine when the two RHEL machines are on the same vlan. Also, ping6, traceroute6, and DNS requests over IPv6 seem to all work fine regardless of what vlans the machines are on. I can telnet over IPv6 between Linux and Solaris machines, that is, the problem only exists when going from a RHEL machine to another RHEL machine. Version-Release number of selected component (if applicable): kernel-2.4.21-27.0.1.EL How reproducible: Always Steps to Reproduce: 1. Put two RHEL machines on different vlans on a Cisco switch. 2. Make sure each machine gets an IPv6 address 3. Telnet from one machine to the IPv6 address of the other machine (you can also use the hostname if that hostname has properly configured AAAA records) 4. Enter your username and then your password Actual Results: You are properly authenticated and the client sees the "last connected..." message. Then instead of getting a shell prompt the client just sits there until you terminate the process. Expected Results: After authenticating you should get a shell. Additional info:
Anyone had a chance to look at this yet?
*PING*
UPDATE: After doing further testing...I have found more specific information about the problem. The problem only happens when machines with MTU's set to 1500 are on vlans that have a maximum MTU size of 9180 (i.e. jumbo frame support). If the maximum MTU size of the vlan is bumped down to 1500 the problem goes away. Now the question is: Is this a redhat-specific bug, a linux-specific bug, a cisco-specific bug, or an inherent "feature" of IPv6 itself? Has anyone at redhat even looked at this yet??????
This bug is filed against RHEL 3, which is in maintenance phase. During the maintenance phase, only security errata and select mission critical bug fixes will be released for enterprise products. Since this bug does not meet that criteria, it is now being closed. For more information of the RHEL errata support policy, please visit: http://www.redhat.com/security/updates/errata/ If you feel this bug is indeed mission critical, please contact your support representative. You may be asked to provide detailed information on how this bug is affecting you.