I am experiencing a rather slow download rate compared to what my ISP has promised me(~50Mbit/s). A speedtest gives:

Download : 5.96 Mbit/s
Upload : 27.10 Mbit/s

Some information that might be useful:

sudo ifconfig
eth0 Link encap:Ethernet HWaddr c8:0a:a9:ac:93:c8
inet addr:213.113.115.213 Bcast:213.113.127.255 Mask:255.255.240.0
inet6 addr: fe80::ca0a:a9ff:feac:93c8/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:1823561 errors:107158 dropped:0 overruns:0 frame:107158
TX packets:1321496 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:1551697513 (1.5 GB) TX bytes:141275623 (141.2 MB)
Interrupt:20 Base address:0x4000

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:912 errors:0 dropped:0 overruns:0 frame:0
TX packets:912 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:27436 (27.4 KB) TX bytes:27436 (27.4 KB)

wlan0 Link encap:Ethernet HWaddr 00:1e:4c:8a:4b:de
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)

sudo ethtool eth0
Settings for eth0:
Supported ports: [ MII ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Supports auto-negotiation: Yes
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Advertised pause frame use: No
Advertised auto-negotiation: Yes
Speed: 1000Mb/s
Duplex: Full
Port: MII
PHYAD: 1
Transceiver: external
Auto-negotiation: on
Supports Wake-on: g
Wake-on: g
Link detected: yes

ipv6 is not enabled. Thanks in advance for any help.