What OS are your real servers running? Do they have multiple interfaces? Is the VIP using DSR? I ask because we ran into a number of ARP related problems with real servers with multiple ethernet interfaces running Linux kernels of 2.2.x and 2.4.x.
-----Original Message----- From: [EMAIL PROTECTED] [mailto:foundry-nsp-bounces at puck.nether.net] On Behalf Of Cliff Fogle Sent: Monday, March 06, 2006 11:18 AM To: Gabriel Cain; foundry-nsp at puck.nether.net Subject: Re: [f-nsp] Interesting problem with ServerIron GT This is just a quick guess. But you may want to configure a server source-ip on the subnet local to the real servers: Server source-ip <ip address> <mask> 0.0.0.0 This is done from the global configuration. If you read the docs you will see that this is usually for source-nat. But it does quite a bit more, including sourcing keepalives from this address and possibly arp requests. -----Original Message----- From: [EMAIL PROTECTED] [mailto:foundry-nsp-bounces at puck.nether.net] On Behalf Of Gabriel Cain Sent: Monday, March 06, 2006 10:00 AM To: foundry-nsp at puck.nether.net Subject: [f-nsp] Interesting problem with ServerIron GT Hi. So I've got an Interesting problem on a ServerIron GT EGC16. I have two mail servers (running postfix) that are being load balanced in the normal, easy way[1]. See below[2] for the software version. Every so often, we get pages from our alerting system (nagios). Those messages are that the 3 addresses, the two real mail servers, and the vip, are down. Unreachable. They don't always go down at the same time, but they often do in clusters; one goes down, then back up, then another goes down. Or both go down close in time to eachother, then back up close to eachother. The events haven't been observed to last longer than about 10 minutes. Most of them are only 3-4 minutes in duration. I've checked the logging on the servers, and they show no interruption in layer 1 connectivity (i.e., no log messages about the interfaces going down, which would show if it had). Arp timeouts occurred to me as a possibility, but I've not been able to get any conclusive data. The log messages on the serveriron are brief, just stating that it went down, and back up. No useful information :^( Our cat6500 says nothing at all in its logs during these events. The real servers are in a VLAN, vlan 20. The nagios system is across our network in another place. The foundry links to our catalyst 6509 via a trunk group of four gig-E ports (i.e., "trunk switch ethe 3/15 to 3/16 ethe 4/15 to 4/16") Network arch is roughly: {corp offices with nagios probe}----[router] | [cat 6500]--------{Internet} | {real servers}-------------------[SIGT EGC16] What have run TCP dumps on the servers and on clients during these events. One thing that I do notice is that arp requests appear to come from the foundry's configured management IP address, rather than the VIP. I don't know if this is a problem or not, but it may be, as the VIP and the management address are in different subnets. This is also confirmed from the log messages on the servers: arplookup 1.2.3.130 failed: host is not on local network Anyway, it's really frustrating, and I'm unsure of where to look next. Has anyone seen this behavior before? Thanks for the help! Gabriel [1] Configuration excerpts: (IP subnet has been replaced with 1.2.3) trunk switch ethe 3/15 to 3/16 ethe 4/15 to 4/16 ! server real mail1 1.2.3.102 port smtp ! server real mail2 1.2.3.103 port smtp ! ! server virtual mail-cluster 1.2.3.101 port smtp bind smtp mail1 smtp mail2 smtp ! vlan 20 name mail-servers by port tagged ethe 3/15 to 3/16 ethe 4/15 to 4/16 untagged ethe 3/5 ethe 4/5 ! hostname sigt-sea-01 ip address 1.2.3.130 255.255.255.192 ip default-gateway 1.2.3.129 ******** [2] show version: SW: Version 09.3.01bTD2 Copyright (c) 1996-2003 Foundry Networks, Inc. Compiled on Jul 07 2005 at 21:17:20 labeled as WXM09301b (3769367 bytes) from Primary wxm09301b.bin HW: ServerIronGT E-1 Switch, SYSIF version 21, Serial #: Non-exist Slot 1 & 2 are: SL 1: B0GMR WSM2 Management Module, SYSIF 2, M6, ACTIVE Serial #: removed 0 MB SHM, 1 Application Processors 16384 KB BRAM, SMC version 5, BM version 21 SW: (1)09.3.01bTF2 Slots 3 & 4 are J-BxGC16 JetCore Gig Copper Module, SYSIF 2 -- Gabriel Cain Senior Systems Administrator PopCap Games gabriel at popcap.com Direct: (206) 256-4243 Mobile: (425) 418-8166 _______________________________________________ foundry-nsp mailing list foundry-nsp at puck.nether.net http://puck.nether.net/mailman/listinfo/foundry-nsp _______________________________________________ foundry-nsp mailing list foundry-nsp at puck.nether.net http://puck.nether.net/mailman/listinfo/foundry-nsp
