PHP ftp_get挂起

Question

I am trying to download a file using FTP in PHP CLI. I have no access to the server where I'm downloading from.

Here's some information about my system.

$ php -v

PHP 5.5.12 (cli) (built: Aug 16 2014 11:36:51) (DEBUG)

$ cat /etc/*-release

NAME="Red Hat Enterprise Linux Server"
VERSION="7.0 (Maipo)"
ID="rhel"
ID_LIKE="fedora"
VERSION_ID="7.0"
PRETTY_NAME="Red Hat Enterprise Linux Server 7.0 (Maipo)"
ANSI_COLOR="0;31"
CPE_NAME="cpe:/o:redhat:enterprise_linux:7.0:GA:server"
HOME_URL="https://www.redhat.com/"
BUG_REPORT_URL="https://bugzilla.redhat.com/"

REDHAT_BUGZILLA_PRODUCT="Red Hat Enterprise Linux 7"
REDHAT_BUGZILLA_PRODUCT_VERSION=7.0
REDHAT_SUPPORT_PRODUCT="Red Hat Enterprise Linux"
REDHAT_SUPPORT_PRODUCT_VERSION=7.0
Red Hat Enterprise Linux Server release 7.0 (Maipo)
Red Hat Enterprise Linux Server release 7.0 (Maipo)

Here's the code.

$ftpconn = ftp_connect(FTP_HOST);
ftp_set_option($ftpconn, FTP_TIMEOUT_SEC, 86000);
$ftplogin = ftp_login($ftpconn, FTP_USER, FTP_PASS);
ftp_pasv($ftpconn, true);
$list = ftp_nlist($ftpconn, FTP_PATH);
foreach($list as $file){
    ftp_get($ftpconn, DOWNLOAD_PATH . DIRECTORY_SEPARATOR . $file, $file, FTP_BINARY)
}

When the script hits ftp_get the file is created with the proper name, but then it hangs for the amount of time specified in ftp_set_option . PHP never writes anything to the file.

I have set 777 permission for the root folder where it's located recursively. I'm also running PHP CLI as root.

sudo php /path/to/php/file.php

Is this a problem with PHP being unable to write to the file? Why is it not throwing any errors? When the timeout is reached, the ftp_get function simply returns false.

Help would be greatly appreciated.

Answer 1

The problem was caused by Amazon AWS instance, certain instances changed the MTU of the network interface.

The solution was as simple as giving the following command:

sudo ifconfig eth0 mtu 1500