Active Sessions being disconnected with 657 error

[Guest.Visitor]

We are having a problem with active Client Access Express display sessions being disconnected with a 657 error, which I believe is supposed to indicate a problem resolving the server host domain name. This most frequently happens at our remote offices, which are using either a hardware VPN device or PPTP over a DSL line, but occasionally happens to users on our internal Ethernet network (this may not be Client Access specific either, since some users with BosaNova TCP/IP emulation experience similar failures). The AS/400 still thinks these jobs are active, and in some cases it takes quite a while to end the job. The only thing I have noticed is that in most cases the AS/400 was going through its normal inactivity timeout routine at the time this is occurring, and another device at the same location (with a similar session ID and IP address) is being disconnected normally. Sorry to go on so long, but this is really a nuisance. Any help appreciated. Doug

[Guest.Visitor]

Doug, You say there are more than one devices in the same location with the same IP address and session id? Looks like you have a network addressing problem. How many DHCP servers do you have in your LAN? Does everybody use dynamic IP address assignment? You should bring this matter up with your LAN administrator.

[Guest.Visitor]

No, they are similar session names and IP addresses--like 192.130.10.1, 192.130.10.2, etc., and session names like SD10RMT, SD20RMT, ... Doug

[Guest.Visitor]

Doug, ~~~~~ DISCLAIMER ~~~~ I am not a LAN or WAN expert, nor have I ever attended any training on LAN management. However, the following statements are based on my past experiences and observations. I really believe in what I am saying, however, I cannot guarantee my solution will work for anyone else. ~~~~~~~~~~~~~~~~~~~~~~ But as you said, any help appreciated. Right? We have encountered situations very similar to what you described. You are most probably suffering from intermittenet LAN (or WAN) congestion problems. I would recommend you get help in monitoring your LAN traffic. In the meantime, you could try minimizing the problem. Check with your LAN administrator if there has been a LAN upgrade recently. Notes: 1. Even a simple memory upgrade to a router-switch or installation of a gateway could significantly affect LAN performance and behavior. 2. LAN congestion is evident if at certain times, you can easily FTP a 1 Kb file to the AS/400, but at the same time, have extreme difficulty trying to FTP a 1 Mb file to the same AS/400. 3. You can affect how the AS/400 handles LAN traffic by altering the line speed and duplex of ETHLINE (via command WRKCFGSTS *LIN ETHLINE) WARNING: Do not attempt to alter ETHLINE until you are sure everyone has signed-off from the AS/400 and that all network related activities have been terminated! ~~~~~~~~~~~~~~~~~~ Event No. 1: For over 3 years, our LAN backbone's rated speed had been 100 Mb, but I always stuck with a uniform ETHLINE default speed of 10 Mb at Full duplex for all our AS/400s. One fateful weekend, our LAN administrator upgraded our LAN backbone's router-switch memory. The following day, most of our local AS/400s started encountering varying degrees of dropped-connection problems. Solution: I upgraded all the problematic AS/400s' line speed to 100 Mb and "Full" duplex, although I retained the link speed of 10 Mb. Aftermath: Dropped-connection problem disappeared in all but a handful of Acer PCs. This was later fixed by replacing all the Acer's LAN cards. ~~~~~~~~~~~~~~~~~~ Event No. 2: Four months after event no. 1, one of our AS/400s started to have intermittent dropped-connection problems. Soon after, a new problem cropped up. Regardless of methodology (FTP, CA file transfer, SNADS, etc.), files of 1 Mb and over could not be trasmitted from/to a PC or another AS/400. This particular AS/400 did not suffer the dropped-connection problem during event no. 1, so I had not altered it in any way. Now, when I increased the line speed to 100 Mb at Full duplex, the problem got worse with increased dropping of interactive sessions. Solution: I brought ETHLINE's speed back down to 10 Mb again. Dropped-connections became intermittent again. I changed ETHLINE to Half duplex. Aftermath: The dropped-connection and file-transmission problems disappeared. ~~~~~~~~~~~~~~~~~~ Hope you find this information useful.

[Guest.Visitor]

Thanks for the detailed info. I'll give these a try. Doug

[Guest.Visitor]

One other method that might help keep WAN traffic down is to tune the AS/400 connection properties on the client. Open Ops Nav, go to the properties for your AS/400 and look at the Connection Tab. On the lower part of the panel is a "Performance" area and you should set the "Where to look up remote port" to "Standard." This assumes you have not changed any of the server ports on the AS/400. With this setting, the client does not need to query the system each time it needs to open a server port, and will reduce network traffic and speed up the initial connection process. Russ