rsh/rlogin strange behavior

Wojciech Puchar wojtek at wojtek.tensor.gdynia.pl
Thu Feb 14 11:29:41 UTC 2013


>
> repeat 100 rsh <host> date
>
> HINT: Set yourself up in /etc/hosts.equiv on <host> for password-less entry
>
> Repeat about 5 or 6 times and then eventually the connection will hang and you won't be able to make more connections for some time.
>
> Next step? Execute "netstat -an | less" and look for oddities (like a mass pile of FIN_WAIT_2 connections).
>
> In our case (ymmv) the final ACK was not being sent leaving the client side stacking up a bunch of connections that take msl.timeout time to expire (iirc). If I do remember correctly the problem happened when the server was using an em(4) driver.
>
> Our ultimate solution was to either switch critical servers to fxp(4) based hardware or roll entire sites over to using key-based SSH (which may work for you -- have you thought about giving ssh-keygen a try? that is, if you're using rsh for the convenience of password-less entry via hosts.equiv for example).
> --

it is FreeBSD 9, em or re or bge hardware but rlogin goes over tun(4) 
interface.

in the same time rcp works fine even for gigabyte file.

any more ideas?


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