Recent posts (paged)
Annoyances while updating F5
I had to upgrade several F5 load balancers from 11.5 to 12.1 in the last weeks. Usually updating F5 is quiet easy, but there are bugs or annoyances you should know: Sometimes F5 asks for re-activating after the first boot into the new version. It seems that you have to install the new version in a specific order to ...
Rare Connection Resets after Linux Upgrade
Problem: after upgrading from Debian 6 to Debian 8 some of the machines lose their ethernet network connection under heavy load for some seconds rarely. You find lines like these in syslog: [2333099.217735] NETDEV WATCHDOG: eth1 (tg3): transmit queue 0 timed out [2333099.217966] tg3 0000:03:04.1 eth1: transmit timed...
Compiling Sendmail on Debian7
Problem: after compiling sendmail on Debian7 with "./Build" sendmail does not recognize hash .db files. You see the following error message: readcf: map access: class hash not available Discussion: ./Build should detect the berkley DB automatically. When devtools/bin/configure.sh finds libdb.so it adds -DNEWDB as co...
Google Maps Marker on Mobile
Problem: A responsive webapp shows a google map with markers that are clickable. On desktop everything works as expected, but on mobile the markers are not clickable. Discussion: After debugging with chrome remote inspector, I found that a div->frame with opacity:0 was lying above (explicit z-index:2) the clickable ...
F5 Drops WebSockets
Problem: F5 LTM is used als load balancer for multiple web servers. When the client opens a websocket connection to the web server, the connection is closed. Discussion: F5 LTM version before 11.6.0 has a bug in the request_log module (profile). The "request_log" module crashes and drops the connection. The bug is a...
Generate CSR using openssl
Browsers started to warn users about certificates with Sha1 signature. Sha256 is needed now a days. So it's time to renew certificates from Thawte, Godaddy, etc You can generate a new Certificate Signing Request with openssl with this command: openssl req -nodes -newkey rsa:2048 -keyout servername.key -out servernam...
ASR Tips'n'Tricks
ASR-1001-X and IOS-XE is sometimes different and sometimes very similar to classic IOS. Update. You can update, the firmware as usual: # copy http: bootflash: # conf t (config)# boot system flash bootflash:asr1001x-universalk9.03.16.00.S.155-3.S-ext.SPA.bin Show SFP (transceiver) info: # show hw-module interface ten...
F5 sending packets to wrong destination?
Problem: You have a network with two upstream routers and an F5 LTM loadbalancer. Even though the default gateway points to router R1 the F5 LTM sends packets to the mac address of R2. Discussion: " This is a feature not a bug". This "Feature" is called "Auto Last Hop". Which means the F5 answers packets allways to ...
MLPPP over L2TP over Ethernet Channel Groups on Cisco ASR
Problem: After upgrading an ethernet port to a channel-group, all MLPPP connections fail on a Cisco ASR 1002-X. The log file looks like this: Jul 31 2015 07:04:44.801 CEST: Vi4 PPP: Phase is AUTHENTICATING, Authenticated User Jul 31 2015 07:04:44.801 CEST: Vi4 CHAP: O SUCCESS id 143 len 4 Jul 31 2015 07:04:44.801 CE...
Google Map from RSS Feed
Problem: Google had a nice feature to build google maps from rss geo information with a simple iframe tag, but this service is discontinued . <iframe width="920" height="450" frameborder="0" scrolling="no" marginheight="0" marginwidth="0" src="https://maps.google.com/?q=http:%2F%2Ftothepin.blogspot.com%2Ffeeds%2Fpos...