Is it only telnet acting like this? What about ping, netcat (nc)? Does it respond promptly? usually delays with logins (ssh but I think telnet does the same thing) I have caused by messed up DNS and reverse lookup entries. But here it is different because it works fine after first try.
I think the default timeout for arp entries in linux is 60 sec (cat /proc/sys/net/ipv4/neigh/default/gc_stale_time) you can run "arp -n" to see if it is still there Did you double check ip configuration and make sure that network, subnet and broadcast addresses are correct? Regards Gregory 2016-02-09 4:04 GMT-05:00 Agblad Tore <tore.agb...@volvo.com>: > Hi, just a long shot perhaps, checking if anyone else have had this > problem and solved it: > > Two Linux servers running TSM(backup server) software, one x86 and on > s390x (RHEL 6.7) > > Both have an extra NIC connected to a separate backup LAN, separate OSA > adapters + separate cables all the way. > > Connection test method: telnet ipaddress 1500 > > Connect from s390x via that vlan and port 1500 into the x86 server works, > but takes 5-10 seconds first time. And again 5-10 seconds if no traffic for > about 5 minutes. > > Connect from x86 same method does not work, unless a connection from s390x > was made the last 5 minutes. > > It seems the arp cache in the x86 server is updated and that server finds > it way after that, but timeout is 5 minutes, so after that it does not find > it's way. > > I took a tcpdump on that backup lan interface, got some help understanding > it using wireshark, and obviously the x86 connection tries does initiate an > arp query to the s390x server that also replies with its mac address, as it > should. Still this does not help. > Route tables also looks as expected, should not cause a problem. > > Anyone having seen this problem ? > If you also have the solution you will make my day :-) > > BR /Tore > > ________________________________________________ > Tore Agblad > zOpen, IT Services > > Volvo Group Headquarters > Corporate Process & IT > SE-405 08, Gothenburg Sweden > E-mail: tore.agb...@volvo.com > http://www.volvo.com/volvoit/global/en-gb/ > > ---------------------------------------------------------------------- > For LINUX-390 subscribe / signoff / archive access instructions, > send email to lists...@vm.marist.edu 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/ > ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu 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/
