We do have multiple interfaces. It seems when net.ipv6.conf.all.forwarding is 0 or 2 it works fine. When it is set to 1, I cannot ping the SLES11-SP1 hypersockets from z/VM. The only reason we care is that there are some Computer Operation scripts that go out and verify various Linux guests and one of the verifications is ping. For now, I have net.ipv6.conf.all.forwarding = 2 for all my SLES11-SP1 guests and all is well with the world, at least my little virtualized part of it. Thanks to everyone. This would have consume large amounts of my time trying to figure this one out.
Peter From: Steffen Maier <[email protected]> To: [email protected] Date: 10/19/2011 06:44 AM Subject: Re: Cannot Ping SLES11 guests from z/VM through hypersockets Sent by: Linux on 390 Port <[email protected]> On 10/19/2011 01:56 AM, Peter E. Abresch Jr. - at Pepco wrote: > Maybe, net.ipv4.conf.all.rp_filter was set to 1. I took one of my > SLES11-SP1 guest and set it to 2. It now pings from z/VM. When I set it > back to 1, it still pings. When I set it to 0, it still pings. I went to a > different SLES11 guest. It did not ping, but once I set > net.ipv4.conf.all.rp_filter to 0, it pinged fine. I returned it to 1 and > it still pings. I am confused. Why is it pinging all of a sudden or is it > just the nature of the beast. I suppose that once you had loosened the reverse path filtering, you got routing cache entries and then rp_filter no longer checks the FIB (forwarding information base == routing table(s)) as long as a corresponding cache entry is still there even if you have set rp_filter back to 1 for strict checking. /sbin/ip route list table cache The routing cache is volatile. You can cross check my assumption by flushing the routing cache after having set rp_filter back to 1 for strict filtering and checking whether ping fails to work again. /sbin/ip route flush table cache > Should I set it to 2 globally? Probably this depends on your network topology and security requirements. Do you have any asymmetric routing or multiple interfaces to the same subnet [1] in the same virtual machine and need such configuration? [1] http://www.mail-archive.com/[email protected]/msg57175.html > From: "Michael O'Reilly"<[email protected]> > Are you by any chance hitting: > "Applying SLES 11 SP 1 Causing Communication Issues" > http://www.novell.com/support/search.do?cmd=displayKC&docType=kc&externalId=7007649&sliceId=1&docTypeID=DT_TID_1_1 >>>> On 10/18/2011 at 06:42 PM, "Peter E. Abresch Jr. - at Pepco" > <[email protected]> wrote: >> We are running z/VM Version 5 Release 4.0, service level 1001 (64-bit). We >> can ping all of our SLES10 guests through our real hypersockets from z/VM. >> however we cannot ping our SLES11 guests from z/VM through our real >> hypersockets. All our Linux guests (SLES10 and SLES11) can ping each other >> fine through hypersockets. z/OS can ping SLES10 and SLES11 guests through >> hypersockets fine. SLES10 and SLES11 Linux guest can ping everything fine >> through hypersockets. The only problem is pinging SLES11 guests from z/VM. >> Has anyone else experienced this problem or have any suggestions? Steffen Linux on System z Development IBM Deutschland Research & Development GmbH Vorsitzender des Aufsichtsrats: Martin Jetter Geschäftsführung: Dirk Wittkopp Sitz der Gesellschaft: Böblingen Registergericht: Amtsgericht Stuttgart, HRB 243294 ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For more information on Linux on System z, visit http://wiki.linuxvm.org/ This Email message and any attachment may contain information that is proprietary, legally privileged, confidential and/or subject to copyright belonging to Pepco Holdings, Inc. or its affiliates ("PHI"). This Email is intended solely for the use of the person(s) to which it is addressed. If you are not an intended recipient, or the employee or agent responsible for delivery of this Email to the intended recipient(s), you are hereby notified that any dissemination, distribution or copying of this Email is strictly prohibited. If you have received this message in error, please immediately notify the sender and permanently delete this Email and any copies. PHI policies expressly prohibit employees from making defamatory or offensive statements and infringing any copyright or any other legal right by Email communication. PHI will not accept any liability in respect of such communications. ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For more information on Linux on System z, visit http://wiki.linuxvm.org/
